Be cautious, you do not know what kind of finish is on your plane.

Different types of finishes may react with each other and cause wrinkling or who knows what kind of reaction? Try you new finish in a small area first.

There has been a trend in recent years away from Dope with the use of Urethane paints and in particular of using spray enamel for color and then using Polyurethane clear over the top as a fuel proofer. Therefore your plane may not have dope on it?

I personally have not used dope in 20 years. But I used to think I couldn't live without it.