Ive been there!!!!
Not sure about rustoleum though.... paint is paint I guess. But you're not painting a hunk of iron.

If you're patient and have a little skills, you can make rattle can look almost as good as the 'real thing'. Yes, duplicolor at autozone/advance auto will work.
Scuff
Prepall
Paint
Then if you want you can clear it too. The clear won't cure like 'real' clear does though. It'll be shiny, but it won't last long if you get stuff on it. Like...gas or brake cleaner. will eat it right off. notice you can spill gas on your tank and still wipe it off and it'll look like it never happened....not the case with duplicolor clear.
But hey...it's a track bike!