If I doodle on some of the robot parts, would it remain competition-legal? I don’t see why it wouldn’t, but I figure its safer to ask some people who know better than I do.
yes it legal as @7996B has said and posted a picture of the game manual rule. I would suggest that if you have any questions on the legality of anything then it would best to first read the game manual. If you have any questions about the rules quote the rule(s) in question and what you are not sure about. By doing this you will most likely answer you question in the process. While it is easy to just ask and get an answer looking thought the game manual and figuring it out yourself is better.
Just read the game manual.