How rare is it

[Ubermcoupe]

I believe that those are "adopted on" dates of when they were officially adopted my the US military. I bet that every design was actually born a year or more before. So, having a M1911 prototype from 1908 or 1909 would be possible.

Indeed.

[Army]

Nope. Most of JB's models were dated at the time of production. ie; M1890 slide action .22. His first patented gun, the Winchester M1885, was a single shot.....neither were considered for military use. Only a few of his inventions were considered for, or adopted by, the militaries of the world.

When the military adopted them, they were often given a new designation, ie; M2 machine gun, M4 cannon, P-35 etc.