I have no idea how Roy called that gun a 2nd Model, unless he was assuming the barrel and cylinder were the identifier. It must be remembered that both Issues had overlapping serial numbers, with the 2nd Model running from 11,672 to 126,361. The 3rd Issue serial numbers were from 1 to 131,163. Bottom line was that there was supposed to be a serial number 126,443 in 3rd Issue, but not 2nd Issue? Barrels are interchangeable, but the bottom line is whether it has matching assembly numbers?? If so, it only compounds the dilemma of determining authenticity.
My thoughts on the hybrid is that it was either a factory lunchbox special, or gunsmith's project. I cannot imagine the factory selling a gun with parts of patent dates missing on the cylinder??