Interior paint questions.

[Squareforceone]

I pulled the old rubber mat out of my truck and found the floor boards to quite solid (for an iowa truck lol) However, there are some spots where the paint is bubbling and peeling that just needs sanded and painted. Now ideally id sand everything down to bare metal and por-15 it but cash is super tight so i was thinking of putting down some black rustoleum for now. Would it hold up well? i have a leak in the cab that leaves water on the floor would rustoleum do a very good job at keeping the rust away? Also was wondering how to find out what my interior paint color is called the sticker in the glove box confused me on which code was the interior paint. Sorry for the long winded question thanks guys.