Just got a 1982 El Camino. Does it require leaded or unleaded gas in it?

Probably unleaded. What kind of emissions items does it have? Air pump? Cat converter? The fuel filler should tell the tale - the unleaded fillers had a small flap inside.

Thanks to all who have responded.

unleaded.. '78 on down to present time, unleaded became widely used

Even if it were manufactured for use in Mexico, it was made to take unleaded fuel with the hardened valve seats. The sure fire way to tell if it did have a cat from new (which would require unleaded fuel) is to look in the fuel filler. If there is a restricter disc, with the small filler opening, then it is made to burn unleaded only. If the filler tube is unrestricted, then the car never did have a cat, so can burn leaded fuel. Of course, leaded fuel will cause other issues, so you are better off with unleaded anyway.