Welcome to Allpar. I have read a source on the internet that claims that the pre-1988 flat tappets and cam can be upgraded to the 1988-on roller tappets and cam. I have never done it and can't vouch for the accuracy of this claim. Many parts suppliers still offer the old style flat tappet set-up.
Having wiped a cam lobe on a hydraulic-flat-tappet engine (a late seventies 360 in my case) wish that the engine had been roller. If a roller cam will install and run properly, you don't have to go so crazy with ZDDP additive or with diesel oil to keep that engine lubricated properly.