3Ms are becoming a rare bird everywhere. 3M discontinued the signal in 2007, sold all the remaining stock of parts. All the molds for the signal were destroyed.
These are Incandescent, yeah I've seen the pronounced fadeout for sure too. If you want to see some L.E.D heads, they might show up at Hurontario & Petworth in Brampton on google maps.
Oh, and the entrance to Square One used to have similar 3Ms with the black backplates. There was even a 5 section one there.