Move on up to T55 now, while you can!
I've had lousy results with outdated Polaroid. I've used "6 month old" and had flaky results; I've used "1 year old" and had consistently terrible results. The chemical package seems to dry up and causes incomplete coating. Even when the chems coated (sort of) completely, the processing was all wrong.. speed obviously off, colors didn't migrate properly, etc. I wouldn't have any confidence in outdated Polaroid for any serious use.