The only reason the pto would have been installed is to run somekind of equipment, like the others have said. It would not have been a Chevrolet option, though the truck dealer could have installed it when the truck was brand new. They are all after market made by names like Chelsea, Muncie, and others. It was never installed "just in case". It might be cool to know the history of the truck and what the pto was used for. I bought one listed in a swap meet ad about 4 years ago from a nice guy in Wisconsin for $45.
About your crank, .060 seems like too much to me as well. I did not know you could get bearings that undersized. My local shop quoted me $160 to turn the crank in my 235. I don't know how that compares to yours, but it's real close to Patrick's price. Good luck.
