Straight 90 or 80W-90 in the differential and tranny.
Steering gear, there is a special lube available, but per GM you can use chassis lube, I prefer the moly base since it does better at lower temps. If you put gear lube in, it will leak out in a hurry.
For the hood badges, go to some of the on-line vendors and look around. There are also some tech pages that spell out the year differences, I think on this board and at some of the vendors. There's also a website about old Chevy trucks that lists all the differences. Think there was a thread about it at
http://chevygmcofkc.org/ I hate to cut and run, but it's a zoo here at work right now.