Stitching at the welt ? Not Reversed ?
Very good. There are as many as a dozen differences between an early, and a late, Brill. In a pic, at the front there is only one guaranteed difference that can be spotted:

late -- the last stitches return as a sort of squared-off "J".

early -- the last stitches return only as a sort of squared-off "L".
From the back the differences are far more obvious.
For a collector I suppose it only helps to know, for rough dating purposes. But if one ever wanted to USE a Brill, one would want the later ones, made for Brill by Rabensburg: the cuff is a structural part of the belt loop, and only he put great effort into how the cuff was sewn to the fender, for strength (early ones with failed stitching abound). He also used double and triple welts in his revolver versions, whereas early ones only had single welts on all autos and revolvers. The doubled welts were the essential part of what we now call a Threepersons design: they were used to jam the pistol into place (no maker has done so, though, since Bianchi in the early '60s, in a Threepersons holster).
This is not a random observation; a thorough study of hundreds of pics shows that there are only two sets of 'markers'; that is, a Brill (or one that looks like a Brill but has no maker's mark) with one or the other difference in the hand sewing of that end of the welt, will always have all the other unique indicators to match. No exceptions have ever been sighted, right down to the backside sewing always being 5 inline stitches on the left (of a rh holster) and 7 or 8 (never 6 or 9) inline stitches on the right (ditto) on a late-by-Rabensburg Brill.
P.S. Rabensburg also made these holsters without the Brill marking, and with the owner's initials stamped instead, on the cuff. It is from a pair of known Rabensburg's (made for their owner personally by him in the 1950s) that we know which is which -- and contemporaneous news stories tell us 'when'.