Blazin you will definitely need a welt. The way I built these is a little tricky and makes getting the stitching right much more difficult. I'm pretty happy with the way these three turned out. The stitching on the back looks as good as the front but I'll probably build any future pancake sheaths different. If you've done much hand stitching, you probably know what I mean front vs back
Just keep in mind a welt doesn't need to be thick to be effective.
Here is a shot of the back of these three.