A couple of comments...The 5 stamped on the grip frame suggests the revolver was intended to be, or was shipped as a 1950 Target 45. A 1950 Target 44 would have a 4 stamped in that location. The stocks date to 1968 or very early in 1969, just before the diamond around the escutcheons was deleted. Based on the serial number, it is quite possible the revolver was shipped before target stocks became available for N-frame revolvers.

Thge 10 1967 indicates something was done at this time, but I don't see any refinishing marks. Possibly a caliber change with a new barrel and cylinder? If the 44 was shipped in 51 or in early 52, the target hammer is probably a replacement for the original. It may be original if the gun shipped in late 52 or later.

Bill