oil pump gasket, yeah or nay

I never use OP gaskets. One thing you can be sure of: it will compress with heat & time. Once that happens, two more things can happen: you get a leak &/or the fasteners come loose....& then with loose bolts....
No gasket, just a thin film of silicon or 518 gasket maker. Keep it around the outside of the body so that none gets into the feed hole.