Lost Cause said
I wish to claim the precedent that all the non-USAF SG teams used their own gear. (SG-3 in BDUs and MCCUUs, SG-4 in Russian gear, SG-25 in ACUs, etc.)
But, is he MILITARY assigned?
If he's military, he's restricted to SI stuff.
Standard operation for all armies, in any country with an army worth speaking of.
Also, I asked my father (Colonel Doctor in the Indian Army) about the rules for military uniform, because my own experience didn't quite cover it too well.
On duty, an officer has to be constantly wearing his uniform. He can wear any where that isn't denigrating to the uniform, off duty.
In combat, you wear whatever is supplied, though some special forces have a very small choice in firearms and armor