My point wasn't that that was possible in an "official" capacity, but perhaps in an unofficial one just to have an idea of what is, in fact, out there.

I see SO much speculation about numbers "there's only one/two of these on the registry" or "there's tens of thousands of those on the registry", etc. Some are relatively easy to confirm (like SWD M11/9's -- one manufacturer with production records on a firearm that was sold almost exclusively to the civilian market) but other things such as M16's have SO many manufacturers that it's nearly impossible to know with any level of reasonable certainty how many there are. Ditto DIAS, etc.

I've seen transferable count (gu)estimates as low as 120k, and as high as 180k. I don't think either of those would be enough to be considered "common use", however.