As far as I know, the Grey Cup was only seen on CBLT from 1952 thru 1957. Beginning in 1958, the CBC televised the Grey Cup nationwide. In 1962 CTV won exclusive rights for the Grey Cup, but after much wrangling, the CBC was permitted to carry the CTV feed. From 1962 thru 1970, both CBC and CTV televised the game and some years CTV crews did the game, and some years CBC crews called the game. From 1971 thru 1986, CBC and CTV pooled the telecast, with CBC calling one half and CTV calling the other, usually CTV on air talent did the first half and CBC taking it from there. From 1987 thru 1990, CBC and the CFL's syndicated network, CFN, each did the Grey Cup, with separate crews and production. Then from 1991 thru 2007, CBC handled the game exclusively.
Starting in 2008, the rights for the CFL is exclusively in the hands of TSN, including the Grey Cup. This will end an incredible 56 year run of CBC doing the Grey Cup.