On Ram Tank, this vehicle is listed as PCC Mar 64, Mar 64 COD and May 65 COD. The comment on the listing is that the status "COD" is condemned.
http://www.ramtank.ca/postwar%20sherman.htm
I don't see much information there regarding the units that operated this particular tank. Perhaps the author of the book on postwar Sherman's may provide more insight. Rod Henderson, could probably be contacted through Clive Law.
With the plaque on the vehicle already you don't need much of a case to prove this is a historical artifact worthy of preservation. There is money available for a pad, sandblast and repaint and perhaps even a re-dedication of the memorial. The biggest hurdle is normally getting a champion in the City to ramrod it and finding a suitable place to display it. No doubt there are hordes of people who want things like this removed and scrapped lest they trigger negative memories for refugees, flower children and despondent Clinton/Sanders supporters.