You may be right Guy. I forgot that this model was reported to have all frames stamped and manufactured before 1899, making all antiques. The question of when it was shipped needs a letter to be sure, but the low serial number frames would have been manufactured early in production as I guessed 1878 was the manufacturing date of the frame and not the ship date.
Perhaps the OP can measure the length of the cylinder? It looks like it might be a 1 7/16" to me?
I agree with the entire evaluation, but doubt if the refinish is factory with a sanded flat hammer axis stud and black vertical top posts.
Yep, longer cylinder, hmm.
Is there a secret about the Caliber. If it is in the .44 range try a .44 R and a .44-40 to know for sure. Could also be a .32-44 or .38-44.
Can also just be a put-together. Have to check if all numbers match. Reminds me of some later Jap contract guns that were ordered with the Russian trigger guard tang but those are usually later in the SN range.
BUT, you never know until you do all your homework !
Something like this with a single line barrel address ... at a "glance", would expect it to have a 5 digit serial number from toward end of the production range. Also check the mechanical condition.
Check the number on the butt, the face of the cylinder, the latch and the cylinder recesses (visible only with the barrel open and latch raised).
Remove the grips and take a look for any marking, numbers, etc on the flat part of the frame under the grips.