OK, so this thing is brand new and gelcoat fiberglass... the guy wants it painted black to match his bike. Guy at the auto paint store tells me I can just clean it really well and spray a couple coats of epoxy on it and then paint it... he says NO scuffing needed

This just doesn't seem right to me, shouldn't I at least red scotch it first? The job is for my neighbor and I want it to be perfect and LAST

Thanks!

It should be in a "sandable gel coat" right now and as the name implies you would sand that. Black and white sandable gel coats are popular with raw parts as they are kind of "self guide coating" when you sand them. For me, I don't trust any aftermarket part nowadays. They don't do a good job of getting off the mold release. I'd clean it with dawn, hit it with a Pres Sol type wax/grease remover, and let it set in the sun for a day. If you are getting any strong resin smell still, let it set in the sun for another day. You want to make sure that piece isn't still shrinking before you paint. Then I'd either hit it with a good scuffing as you are thinking or 400 before moving into the epoxy.

Thankyou Darrell, very much.

Now, I also have 2 plastic side pieces, covers, that go on the side of the bike... I don't know what they are called (I'm not a bike guy), They are molded in color and hard plastic, he wants them jet black also... I was planning on sand and epoxy for them, but do I need an "adhesion promoter"?

Yeah, if they are some type of "raw" plastic (no visible primer) then that is exactly what you need. Even the el cheapo rattle can Bulldog would be fine.

Thanks Darrel, youve been a great help, I'll post up a pic when I'm done... next week sometime