That brass back strap and trigger guard on the Single Action are not original Colt S.A. parts, plus there is no matching serial number on it to match the rest of the frame. Looking at the base of the strap you can see where it doesn't quite fit.
If it is a Colt, the 245xxx serial number indicates that part of the revolver was mfg'd in 1903.
Looks like someone decided to play around with some after market parts on an old frame. I believe you have a "shooter" so long as it is not screwed up in the barrel or cylinder ..... and you don't feed it some fire breathing loads.
Nice Govt. Model Colt, however.
L.W.
