More gas filler door questions!!!

This thing either fell off or someone stole it. I ordered a new one from Toyota of cool springs and it came in black. It's also plastic. To me it does not look like a surface that is ready for paint. I also feel like my original gas filler door was metal. Was it just painted plastic. Can somebody check they're painted fuel door with a magnet please. Anyway I think I may just spray it with a flat black Bedliner in a can or try using the white raptor liner in a can Obviously it would be a textured finish with the Bed liner spray. Any body guys have any idea how much it would be to paint super white? Thanks. Pic for attention.

 

The original door is plastic (mine is) and I think is just a snap in type fitting to that black piece. I think I've seen a couple of posts that reported the same issue.

 

pics of the new piece.

 

Wouldn’t think a body shop would charge that much to paint and color match it for you