Sheet metal questions

[Racefan]

Can someone give me some insight to whether or not the factory vinyl top cars were painted/primed under the vinyl? I am not finding anything under the current (2nd) paint job there. They left the factory paint under the rest of the car so not sure why they would strip it, unless to get rid of adhesive. Also, at what point would you guess consider actually using the replacement roof panel. My car has some rot on the top lip the windshield sits in. Schoenye, I am getting ready. Driver's side needs a FULL quarter.