Mark, your collection is truly awe-inspiring! I've noticed that most of your rifles/PCCs have an optic of some sort on them, including some I would've thought went prohib before those optics would've been available (thinking the C1 and Uzi). Are those optics just for show or could you still get ATTs for those firearms and you actually got to shoot them with the optics on? I'm not well-versed on when they stopped issuing ATTs for prhibs since I'm pretty sure I'm too young to ever have been able to own any. Would be pretty cool to shoot an Uzi or Mac-11 with a red dot!
They stopped issuing Special Authority to Possess (SAP) permits for the transport of prohib 12(x) long-guns in the Spring of 2005, just as I was posted from Gagetown NB, to Edmonton, AB. We had one last big shoot in NS IIRC, with the "Maritime CGN Crew" as it existed back at the dawn of time circa 2005, and then that was it. None of the guns (with the exception of my restricted PCCs) get to the range any more, which is a ridiculous waste of potential enjoyment at ZERO RISK to the public. But I digress...
A buddy and I won the PCC Bowling Pin Converted-Auto Knock-Down Challenge back in 1996 at the Wolverine Supplies/Fprt La Bosse Gun Club competition weekend. I used the C1 SMG with an earlier iteration of the forward-mounted Red Dot (30mm tube unit) and he used my MP-5 with the Armson Occluded Eye Gunsight (OEG) which uses the Bindon Aiming Concept (Google is your friend). We managed to clear the bowling pins off of the top of a rimmed 40-gallon drum in the shortest amount of time possible in order to win that portion of the overall match, provimg that even back in the prehistoric days of red-dots on CQB firearms, they provided a clear winning advantage. I have personally never looked back, being an early adopter of red-dot optics on PCCs and handguns (1996), LPVOs on combat rifles (2008), and so forth.
So to answer your question, the optics on the Prohibs are definitely not just for show. That said, they are also not my most up to date examples given that they currently occupy safe-queens. Those guns werem't always safe-queens though, and red dots did exist back when we were still permitted to discharge those "overly dangerous" firearms. They just weren't so small back then.
As a side-note, none of the optics mounts on my firearms are permanent, including the Weaver Rail on the C1 SMG. That rail is retained by screw-nuts on the underside of the ventilated shroud. The system is rock-solid, but also easily removable in order to restore the firearms to its original, "as issued" configuration.