Mako, are you sure Colt actually marked any guns .44-40 in the 1800s? I'm aware of the Colt Frontier Six Shooter barrel markings and the little. 44CF mark sometimes found on the trigger guard, but I didn't think Colt marked any 1st gen SAAs .44-40. But I'm not terribly experienced and am mostly parroting those who know more.
Jim,
That is a good question. I have seen Gen 1s marked as .44-40, but I actually don't know when they started marking them as .44-40. This is a Gen 1 below.
But, Colt's was bad about their caliber marking as we were discussing with the .38 Colt. If someone here is a SAA expert, please chime in. I have the two book set
The Colt single action revolvers: A shop manual--volumes I & II by Jerry Kuhnhausen and small pocket serial number and feature identifier but I would not call myself a SAA expert.
This is why I enjoy these discussions I get schooled a lot.
~Mako