I don't get the question. I have four 51t cans (which is four too many! --NEVER another AAC can, NEVER). You need a 51t mount? You need a non-AAC 51t or a non-AAC mount to replace 51t? What's the form 1 got to do with it?
Besides AAC, I think there are several places that make a 51T mount.
FWIW, the best way to get a solid mount for one of these is to buy ten of 'em. Pick the one that locks up best, send the rest back. Yeah, it sucks, but it's the only way I've found to get good solid mounts without fucking up the warranty or finishing AAC's work.