Production date?
 

Just sitting around enjoying my 1900 Commercial ser # 4672....and it occurred to me it would be nice to narrow down when it was "born". I know I've seen info that says the US test guns were made OR shipped in Oct 1901...as they begin at #6100, would my gun be a 1900 or 1901 baby?

Old Model production cannot have begun before May, 1900--that is when the Swiss accepted the Parabellum as their service pistol and finalized the design. The U.S. Test pistols starting in the early 6000 serial number range were delivered Octobrer 26. Fastest trans-Atlantic travel at that time was one week, shipping likely took a little longer. No way to know how long production actually took. An unscientific look at the numbers suggests that your serial number probably falls into a rather large statistically grey area which could either be late 1900 to early 1901, if you were to press me I might lean toward 1901 but I would not let you claim it on my authority.

--Dwight