When I did my 87 TA; I scuffed the bumper covers and side skirts, minor body work (flexible filler, used a 2 part epoxy suitable for urethane to repair a crack). This is where it gets murky; I know I used Bulldog adhesion promoter, but I can't remember if I applied it to the substrate and then put my epoxy sealer over it, or vice versa. The next day I applied Bulldog (2 very light coats, heavy coats can cause problems) and shot my base clear over the top.
Im not sure if you need the sealer or not; but the base I used didn't cover great, and I wanted an even substrate. 4 years later and the bumpers look great; the rest of the body is starting to show its age now (parked outdoors, sees rain, drive down a dirt road quite often)