Would it matter if one gasket is .038 and one is .039 compressed thickness, the one on the passenger side is .039 and I was gonna buy a gasket that is .038 compressed thickness but didn't know if the different thicknesses would matter I had to pull off the driver side head due to it leaking.

If you sucessfully address why it was leaking & change the gasket the slight diff will not cause any probs. But for reference what gasket part #'s are you going with

Fel-Pro 1008s are cheap, and .039" thick, why not just replace with the same size gasket?

or 1009s if it's a big block

But it really doesn't matter. You're talking about something like 0.25cc.

R.