Hmm... where to begin, exactly how old is the rem?? Ask yourself a couple of questions first; why is an "older" shotgun in such good shape?? Why so cheap?? Probably from lack of use, that answers the first ?. but what about the cheap part? I'd try to track down the previous owner and find out a little history first. You know the saying,"If it's to good to be true...."
As for your question, yes it will handle 2.75" shells unless other wise specified on the barrel. Off the top of my herad the only scattergun that doesn't handle 2.75" shells is the Mossberg 935. Why?? Because it's designed that way.