Agreed. The Commander in Chief is a civilian without question. However, I believe in the eyes of the Supreme Law, he is titled a "civilian officer", along with the Secretary of War et al, vis-a-vis
United States v. Burns (1870). Perhaps I'm overreaching, but I do think the U.S. CODE pertaining to civilian impersonation of an officer applies as the CiC is a civilian officer and beyond that the highest ranking officer in the entire military body.
Sorry, I think you ARE overreaching here. The President (or in this case, the Pres__ent) has authority over the military ONLY AS the civilian that he is. He is not a military officer in any conceivable way, shape or form. He is merely the apex of the pyramid, but it is only one hat that he wears.
In the sense you’re intimating, no, the US Codes do NOT apply to the POTUS or even the pretender-in-chief.