I had "hooligans" wings once I completed PTS, and I didn't do P Coy, in fact, I've never been to Aldershot in/out of uniform. Rules may have changed, but I think MATZ is on the money. My guess is that the "appropriate selection course" for 21/23 at the time was Selection.
RN may have changed the regs., but I joined BRNC with a lad who ex-RMP Para, and he put his wings up. He (a Midshipman) and the Captain of the College were the only people there at the time sporting them.