diff --git a/src/stdatamodels/jwst/datamodels/schemas/specwcs_miri_lrs.schema.yaml b/src/stdatamodels/jwst/datamodels/schemas/specwcs_miri_lrs.schema.yaml
index 3721ef8b..9bfaed3a 100644
--- a/src/stdatamodels/jwst/datamodels/schemas/specwcs_miri_lrs.schema.yaml
+++ b/src/stdatamodels/jwst/datamodels/schemas/specwcs_miri_lrs.schema.yaml
@@ -2,14 +2,12 @@
 ---
 $schema: "http://stsci.edu/schemas/asdf/asdf-schema-1.1.0"
 id: "http://stsci.edu/schemas/jwst_datamodel/specwcs_miri_lrs.schema"
-title: MIRI LRS Spec Schema
+title: MIRI LRS Fixed Slit Specwcs Schema
 allOf:
 - $ref: referencefile.schema
 - $ref: keyword_pexptype.schema
 - $ref: keyword_exptype.schema
-- $ref: keyword_readpatt.schema
 - $ref: keyword_filter.schema
-- $ref: keyword_band.schema
 - $ref: subarray.schema
 - type: object
   properties:
diff --git a/src/stdatamodels/jwst/datamodels/tests/test_specwcs_mirilrs_datamodel.py b/src/stdatamodels/jwst/datamodels/tests/test_specwcs_mirilrs_datamodel.py
new file mode 100644
index 00000000..a66b4d70
--- /dev/null
+++ b/src/stdatamodels/jwst/datamodels/tests/test_specwcs_mirilrs_datamodel.py
@@ -0,0 +1,59 @@
+import numpy as np
+from stdatamodels.jwst import datamodels
+
+
+def test_miri_lrs_specwcs():
+    """Test the MIRI LRS specwcs data is loaded correctly."""
+    xc = np.array([1.0, 2.0, 3.0])
+    yc = np.array([4.0, 5.0, 6.0])
+    wave = np.array([12.4, 13.4, 14.5])
+    x0 = np.array([1.0, 2.0, 3.0])
+    x1 = np.array([1, 2, 3])
+    x2 = np.array([1, 2, 3])
+    x3 = np.array([1, 2, 3])
+    y0 = np.array([1, 2, 3])
+    y1 = np.array([1, 2, 3])
+    y2 = np.array([1, 2, 3])
+    y3 = np.array([1, 2, 3])
+
+    d = np.dtype(
+        [
+            ("x_center", np.float32),
+            ("y_center", np.float32),
+            ("wavelength", np.float32),
+            ("x0", np.float32),
+            ("y0", np.float32),
+            ("x1", np.float32),
+            ("y1", np.float32),
+            ("x2", np.float32),
+            ("y2", np.float32),
+            ("x3", np.float32),
+            ("y3", np.float32),
+        ]
+    )
+    wavetable = np.array(
+        [
+            (xc[0], yc[0], wave[0], x0[0], y0[0], x1[0], y1[0], x2[0], y2[0], x3[0], y3[0]),
+            (xc[1], yc[1], wave[1], x0[1], y0[1], x1[1], y1[1], x2[1], y2[1], x3[1], y3[1]),
+            (xc[2], yc[2], wave[2], x0[2], y0[2], x1[2], y1[2], x2[2], y2[2], x3[2], y3[2]),
+        ],
+        dtype=d,
+    )
+
+    model = datamodels.MiriLRSSpecwcsModel(x_ref=430, y_ref=400, wavetable=wavetable)
+    assert model.meta.instrument.name == "MIRI"
+    assert model.meta.instrument.detector == "MIRIMAGE"
+    assert model.meta.reftype == "specwcs"
+    assert model.meta.x_ref == 430
+    assert model.meta.y_ref == 400
+
+    # for slitless case assert the v2/v3 vertices are None if not in the file
+    assert model.meta.v2_vert1 is None
+    assert model.meta.v2_vert2 is None
+    assert model.meta.v2_vert3 is None
+    assert model.meta.v2_vert4 is None
+
+    assert model.meta.v3_vert1 is None
+    assert model.meta.v3_vert2 is None
+    assert model.meta.v3_vert3 is None
+    assert model.meta.v3_vert4 is None
diff --git a/src/stdatamodels/jwst/datamodels/wcs_ref_models.py b/src/stdatamodels/jwst/datamodels/wcs_ref_models.py
index e63fdc70..54aa5455 100644
--- a/src/stdatamodels/jwst/datamodels/wcs_ref_models.py
+++ b/src/stdatamodels/jwst/datamodels/wcs_ref_models.py
@@ -29,7 +29,7 @@
     "NIRCAMGrismModel",
     "NIRISSGrismModel",
     "WaveCorrModel",
-    "MiriLRSSpecwcsModel"
+    "MiriLRSSpecwcsModel",
 ]
 
 
@@ -430,27 +430,31 @@ class MiriLRSSpecwcsModel(ReferenceFileModel):
     v3vert4 : float
         slit vertex 4 in V3 frames
     wavetable : numpy  2-D array
-        For each row in the slit hold  wavelength, and 
-        x center, ycenter, x and y box region cooresponding to the wavelength
+        For each row in the slit hold  wavelength, and
+        x center, ycenter, x and y box region corresponding to the wavelength
     """
+
     schema_url = "http://stsci.edu/schemas/jwst_datamodel/specwcs_miri_lrs.schema"
     reftype = "specwcs"
 
-    def __init__(self, init=None,
-                 wavetable=None,
-                 x_ref=None,
-                 y_ref=None,
-                 x_ref_slitless=None,
-                 y_ref_slitless=None,
-                 v2_vert1=None,
-                 v2_vert2=None,
-                 v2_vert3=None,
-                 v2_vert4=None,
-                 v3_vert1=None,
-                 v3_vert2=None,
-                 v3_vert3=None,
-                 v3_vert4=None,
-                 **kwargs):
+    def __init__(
+        self,
+        init=None,
+        wavetable=None,
+        x_ref=None,
+        y_ref=None,
+        x_ref_slitless=None,
+        y_ref_slitless=None,
+        v2_vert1=None,
+        v2_vert2=None,
+        v2_vert3=None,
+        v2_vert4=None,
+        v3_vert1=None,
+        v3_vert2=None,
+        v3_vert3=None,
+        v3_vert4=None,
+        **kwargs,
+    ):
         super().__init__(init=init, **kwargs)
 
         if init is None:
@@ -486,6 +490,7 @@ def populate_meta(self):
         self.meta.instrument.name = "MIRI"
         self.meta.instrument.detector = "MIRIMAGE"
         self.meta.reftype = self.reftype
+        self.meta.instrument.filter = "P750L"
 
     def validate(self):
         super(MiriLRSSpecwcsModel, self).validate()
@@ -497,7 +502,7 @@ def validate(self):
             if self._strict_validation:
                 raise
             else:
-                warnings.warn(traceback.format_exc(), ValidationWarning)
+                warnings.warn(traceback.format_exc(), ValidationWarning, stacklevel=2)
 
 
 class RegionsModel(ReferenceFileModel):