Actually Rigga, mine is not unqualified speculation! I suspect from your screen name, you and I both started life in the Air Force as the same trade? I left, passed my BCAR Sect L, converted to a restricted 66 B1.3 licence, removed my electrics restriction and also added B1.4 & C categories to my engineers licence, before going on to learn to fly!
I've seen many "non permanent" mods to airframes fitted by far more cowboy engineers than discussed here. Simply put, a non permanent, removable Gopro mount that does not make ANY permanent changes to the airframe do not require any approval, nor a CRS for fitting & removal - you can buy ipad mounts on the web which fix to control columns for heaven sake - these have far more hidden danger than a 250g camera fitted to a skid tube!