Could anyone offer up some info on the types of RV2 compressors that seem to be available online. When they're advertised as re manufactured, does that mean they now accept the newer type gas? I've seen four seasons and Spark ones advertised as well as ones that seem to be original, but i don't know too much about them. Are the Four Seasons and Spark ones aftermarket units or were they original suppliers? Going by the pics on eBay, they seem to have the same or similar cast numbers on them. I'm looking at getting an original type compressor for a 70 440 but not sure how to sort through all the different ones available. Looking forward to your views. Cheers.