With the barrel and cylinder changed, the revolver must have originally been in a caliber other than .45 ACP. I think Muley Gil is correct about the gun being a .38/44 Outdoorsman. The revolver shown below was rebuilt by S&W in 1955 to a 1955 45 Target starting with a 1950 45 Target that was shipped to Remington Arms. They returned the gun to S&W and asked for the rebuild. All of the numbers on the various parts match (barrel, cylinder, yoke, and grip frame).
Bill