How wonderful that you have his old gun! That is priceless! You can contact Colt, and for a fee ($100+ dollars last I checked) they will supply you with a written record on Colt letterhead of when the gun left the factory and where it was shipped to. That said, Colt never has made a SAA with a floating fireing pin. But there were some Custom gunsmiths in years past that thought that it was the greatest thing in the world to convert a SAA over. Probably the greatest part was the money it put in their pocket. It shows your father cared enough about this Colt to have it converted. I'm sure that was an upgrade in his eyes. As for the crack, if the gun is nickeled, it could just be a break in the edge of the nickle plating. Best you have a good gunsmith look it over and check that out. Congrats on your gun, many of us wish we could have had a gun from our father. 44 Man