It does look like it might be all 1 piece in the service manual. Tim would know for sure, obviously.
However, if you're talking about the flat, relatively soft, plastic that I think you're talking about: I just checked and it really doesn't look painted to me.
It sounds like whatever the serviceguy used etched the plastic.
Have you tried some rubbing alcohol, WD40, +/or peanut butter (creamy) to see if it may be surface only? You could also try Mother's "back to black" to see if that might fix it.
You might even be able to buff it back since I bet under the etching (which it probably is, but those prior tips are worth a shot if by chance it's not) is clean black.
However, if you're talking about the flat, relatively soft, plastic that I think you're talking about: I just checked and it really doesn't look painted to me.
It sounds like whatever the serviceguy used etched the plastic.
Have you tried some rubbing alcohol, WD40, +/or peanut butter (creamy) to see if it may be surface only? You could also try Mother's "back to black" to see if that might fix it.
You might even be able to buff it back since I bet under the etching (which it probably is, but those prior tips are worth a shot if by chance it's not) is clean black.