The number on the bolt usually isn't a serial#..the Danes did electro-pencil serial#'s on the bolts of their M1's and I think they're the only ones who did. Usually what you see is a drawing #(D28287) followed by a revison number (-19 for example) and then the initals of the maker (SA). Post war made bolts will start with a 65 number pre fix (6528287) and Maker (SA) under this on WWII and post war bolts will be the heat lot number (A8, for example) The heat lot numbers are important if you're restoring a rifle, not only should the revision # be correct but the heat lot # should be as well, records of heat lots were kept and one could trace when a bolt was made from the heat lot, I've got Scott Duff's books on the M1, and could look up the bolt for your rifle, I'll need the serial number, Just Im me. Or ask around over at the jouster site (www.jouster.com) if you want to learn about M1 Garands that's the place to go and ask.It's probably the best M1 site on the net. I'm assumng the Breech bolt Assembly numerich is selling sounds to me like the complete bolt.. ejector,friring pin,extractor, all assembled.(I would however, call and ask) The M1 can easily be converted to shoot .308 all that's needed is a M1 barrel in.308, you would use the same en-bloc clips that you would use for 30-06. As far as slings go.. for WWII era rifles either leather or canvas would be correct, for postwar rifles I think canvas would be correct.