That'll be three diff locks then Mike. One centre, one rear and one front.
If you've the funds and space and time to do this one up then go for it IMO.
Ask yourself this, Would I regret not buying it?
Then, when you've bought it, ask Will a Lexus V8 or a V8 from a 100 series fit in it?
An 80 for $1000? It's worth more than that in parts! I think I'd bite his hand off TBH. You would pay £1000 here for the axles alone. Leather if not too bad can have some seriously nice professional repairs or you have the chance to do a custom interior. Rust underneath needs quantifying. If it's a little surface rust and most is sound then good. Even a bit of replacement is acceptable for that price. There's 80s for sale over here that are complete dogs asking £4000 plus.
Normally buying a cruiser you would check everything works. Diff locks can stick and sometimes disintegrate with our road salt but I don't suppose yours would be that bad. But really at that price it's really unlikely there going to be anything else major wrong with it.
I think there's threads on here about what to look out for but most things can be corrected.
Good luck with it and look forward to seeing some photos of your current and new trucks.