Yep.... 100% correct for resto's.
Epoxy on bare metal and then sealers/fillers.
Epoxy primer will have 15X's the adheasion than bare metal to fillers and sealers. The protection is nice too
Don't use a sealer when you go to paint. Get your primer all sanded down to 600G and use basecoat directly on the fresh sanded primer. You'll retain more gloss with less die-back.
Hope that helps,