Not necessary. Depends on the production year, the month and probably the day.
I personally had two Yashica LMs (non-MAT) with incompatible cases: in the later model the manufacturer has shifted cold shoe by about half inch.
As far as I know this was often the case for Yashica: tweaking both internal and external parameters of the same model for whatever reason.
Also could be parts sourcing from different vendors.
Anyway, in my experience a sharp knife and leather-working skills will do the trick
I did some comparisons based on the photos of both the camera I ordered and the case and the cutouts all look close enough that it's worth a shot. If not I guess I'll re-sell it!
Turns out it fits just fine with no "modifications" needed. It is a minor annoyance that these cases don't sit level on a table due to the snap flap on the lower front, but I feel much better knowing there is some small measure of protection for the camera, plus it's easier to hold and carry.