Boimler has his Starfleet recruitment poster seen in “Those Old Scientists”, but Number One’s face is obscured every time it’s on screen.
I'm 99% sure they were just being subtle (which I like), but 1% of me wonders if there's something in the actors', in this case Rebecca Romijn's, contract that says they have to be compensated if their likeness is used, even a cartoon likeness. And if so, sometimes the budget doesn't quite stretch far enough.