Guys... the serial number on this one is still visible under the second number. The OP said "almost erased. Looks to me like it was way overpolished, not deliberately defaced. It is still legible... and legal.
Give the poor guy a break, not a heart attack. Could be anything... my educated guess is that it's a foregn military arsenal rework, not a US rework. Greece? Turkey? Korea? Could be any of them. The number is a rack-number. Nobody would try to pass off a 3 digit number as a serial number.
Back to the OP: It's a mismatched parts gun, not that uncommon to see. It's a shooter, not a collector. You might very well trade out that slide to someone else and find a Colt slide for it, should be a fun and easy gunshow project to see and swap with any of the parts dealers that specialize in .45 parts.
Last edited by Willie Sutton; March 8, 2012 at 11:00 PM.