It is probably fine. As others have said, the carrier to lens flange is the critical data.

BTW-speaking as a very old....errrr.....I mean experienced mechanical engineer/product designer, I decided to stop using the top of the lens for alignment and use the lens mounting are instead. The reason is that in the design of the lens, a critical dimension for the performance is the perpendicularity of the lens axis (and thus lens mount) to the lens board. They could care less about the end of the lens and probably don't control it nearly as well since it has no effect on the performance of the lens. Controlling any dimension that doesn't add to performance is a waste of money. I checked this theory with a Leitz (modern 40mm) lens and a Schneider and the ends were a fair amount off compared to the base. Is it enough to make a difference...I have no idea....but I figured I might as well measure of the lens board mount since I could.