I bought this Rock-Ola (1,753,xxx with undated Rock-Ola barrel) in the early 1990's from the estate of a weapons accumulator. Anything and everything related to firearms with lots of surplus from the golden age for military surplus in the late 1950's. The carbine is used, but not abused and 100% Rock-Ola with the possible exception of the front sight, marked PO-B. Nothing in Carbine Club records or in "War Baby!" suggest that IBM sent any parts to Rock-Ola. The finish wear of the barrel and the front sight suggest they have been together for a long time. If this was a field replacement front sight, why would the staking of the pin and key be exactly the same as seen on other Rock's with TR, R and RP front sights? I feel that the possibility that this was a clever restoration is zero. I saw another Rock-Ola on Auction Arms a few years ago that had a PO-B front sight with the signature Rock-Ola staking. Anybody have another example or comments on the photos?