I can't say exactly when each model was debuted, but I have some small notes which may give you some idea of when they were shipped from the Canadian division of EMD -
a GP-7 unit was delivered to TH&B in 1950
a GP-9 " TH&B in 1954
a GP-30 " CPR in 1963
a GP-35 " CPR in 1964
a GP-38 " CPR in 1970
a GP-38-2 " CNR in 1972
and, in 1966, the Ontario Government took delivery of a GP-40
My notes end in 1974
Hope this info is what you need