After blowing up the stitch pattern on the sheath, it seems to be an angle stitch pattern to me, indicating that it was sewn by Clarence Moore.
Here is another clearer stitch pattern on a Moore sheath, another model 7, illustrating the offset stitch pattern.
Finally, A Heiser sheath stitch pattern.
So based on what I observe, it appears that Clarence Moore made and stitched the sheath, and as Joe said, Heiser stamped it and put throat rivets on it.