I really hope this is the correct area to ask.
Be gentle it's my first fixer upper! hahah

So I have a '86 k20 that I'm attempting to fix up. I have a friend who has a parts truck that he said I could pick off if anything would work, but I believe its a 94 silverado. I also could purchase an '81 k5 for dirt cheap.
I looked in my area and there's really no older chevs for sale at all.
Could I use either one of these vehicles for parts? I'd assume the 94 would be too "new", but what about the '81?

Any tips would be great!
Thanks!