[drunken monkey]

you gotta be careful when you paint over unsanded, unprimed plastic.
The reason it comes out so smooth and flat is because that's how it comes out from the moulds. Normally, you'd want to give it a good wash to make sure any release agent is removed. Just a warning but it has been known that paint that has been layed on, let's just call it "untreated" plastic doesn't always hold onto the plastic as well as it could/should and has been known to crack/chip more easily as it cures and shrinks.

In short, handle with care.....