Cool!
I have a pair of M-1873's that in the 5000 serial number range, which means that they were built the 3rd week of the 3rd month of the first full year of production.
BTW, I would be in the market for US M-1873 serial# 5725 if anybody knows where it is.
I forgot to mention S&S Firearms should have a repro cleaning rod for it.