Ok so this was dropped off at my house by someone who knows I collect vintage bikes, I started to look up serial numbers but then got really confused B49852= built 1957, which does not make any sense because schwinn did not sell any DX/Excelsior style frames in 1957 please correct me if I'm wrong. I also know schwinn's factory burned down in 1948 so I know it could be a reused serial number, really I just want to know if this is a real prewar Excelsior or a 46/47 Dx frame that someone put the wrong badge on. I also looked at the crank set for a date, it was stamped 11-50A which I think means 1950. I also know schwinn stopped putting sweet heart sprockets on bikes after 1954. I would also like to know a value just so I know if this is even worth trying to fix. there are a few things wrong with the bike, wrong fork, wheel set is dead, seat post is jammed down in the bike, i.e. really hard to get out. The frame has been repaired at some point, and it's really crusty rusty like beyond anything I've had to deal with before.