When they came out with the hypoid design, they also made s new lubricant for it. the gear design literally squeezes the lubricant out from between the teeth so that is the stuff you want to use.
I would guess it would take a while to find a paper gasket for your 1 1/2 ton rear cover. RTV made for auto use will give you a more modern complete seal that will never leak.
Yes the axle gaskets are aluminum. You won't find new pins and you may not find the pin locks. The springs would be a rare find too. The best idea is to be as careful as you can taking it apart and only replace what is broken. Most wheel cylinders can be rebuilt. Mine were pitted so I had them done by a professional shop who installed stainless sleeves.
