You wont be using a cork gasket for the oil pan, unless you make your own, nobody sells them, not even Toyota, you use a form in place gasket(FIPG).

The 4x4 oil pan, and the starter from the '87 as well as all of the components should bolt right up to the '83.

If the rebuild of the '87 is a short term project, I would do a compression/valve clearance check on the '83 and run it. If comp is good I wouldn't be concerned w/the HG, and if there are no plastic guides in the '83's oil pan, and the t-chain doesn't rattle, I wouldn't worry about it either. However, if you are going to be making trips into the back country or long road trips in it, it would be good for the peace of mind to pull the head and check the valves, replace the T-chain, check the pistons etc., the extra $ should be recouped when you sell the engine later on.