Welcome! This is not my area of knowledge, but your gun is a Single Shot Second Model, probably shipped in about 1907. The barrel stamping reads ".22 Long Rifle CTG", the last an abbreviation of cartridge. Others may recognize the engraving style, or perhaps the engraver himself, but the serial number has definitely been redone (the original would have been in small numbers and in the opposite direction on the bottom of the grip frame).

Do you have a family story behind it? Hope this is helpful.

__________________
Alan
SWCA LM 2023, SWHF 220