Restoring Evaporator Box

[71CHEVYSHORTBED402]

Some questions about restoring an evap. box.

The box took some over-spray long ago with black aerosol. So first order is to remove it. I know a guy who can blast it, not sure what material he uses (black something), but it's much finer than sand. Is there a better way considering these are plastic?

I know some people remove the rivets for the bracket, but I think I can away without doing that. A finish guy and I agree that he paints what's black first, then clear coat the entire unit. I think these had a satin sheen, does that sound right for a restoration?

Is there a way to remove the door flapper on these without damaging it? The flapper is still good. If he needs to paint around it OK, but I'd rather remove it cleanly if possible. Unless I'm missing something I don't think it can be removed, similar the A/C diverted flapper. Makes me wonder how they assembled them to begin with.

Thanks!

Thank you