Your image below, Phil, 'brightened' to show the central line between two main welts (N.J.'s typically were two different thicknesses of leather, by a lot):
SAM_2119.jpg
A better pic would show MORE layers; one main welt tapers to nothing (called skiving) to accept another welt that is also skived; then the muzzle will have yet a third layer that appears to be to enlarge the pocket for the revolver barrel there.
brill late (9).jpg
The 'lip' of a Sunday scabbard is ALWAYS sewn to the tip of the fender, no matter which saddler made it -- or it's not a Sunday scabbard. N.J. used a hand chain stitch (looks like a chain of stitches laying on top of the backside of the leather, which it literally is) while Kluge used a straight hand stitch as for the main welt stack.
muzzle chain stitch (2).jpg