I seem to recall a lot of discussion about this from years ago too. The adult content warnings are intended mostly for preview images and obvious sexually explicit content. Certainly, you will need to verify that with Support if you are concerned about it, but I would guess, as others have suggested, that as long as your model is covered up in the preview renders and there is no blatant nudity or sexually explicit contents in the scene, you should be fine. An anatomically correct, clothed character isn't really what the adult warnings were intended for I would assume.
If we are incorrect in that assumption, it would be helpful to be made aware of it. I can't seem to find anything in the TOS about it. Obviously, sexual devices or explicit/suggestive content should have a warning, but a clothed character does not fall under that umbrella.