A fun video, detailing a quirk of the handmade FN M1900 copies that I was not aware of. It made me get mine out (see post #6 above) to check its serial number (which is
not 26063).
In the Rock Island Auction Co. sale I provided a link to in post #30 of this thread, it turns out one of the four pistols is serial numbered 26063 and another is 126063.