Hi Bill
best I can say is clean it up and give it a go, with out seeing the back it's impossible to offer an opinion
assuming you know that type 55 (as with all polaroid instant materials) has been discontinued, I have to ask what you are hoping to do?
are you planning on buying a lot of stock, it stores well if left unopened, I've used 4 year old film with no problems, if you are then surely you should also invest in a good working back as you don't want to waste your precious film on a dodgy back.
enjoy it while you can and if you have any further questions ask away