It's sure different than the manual mirror for 1970 Cdn Pontiacs (or US Pontiac's for that matter). Maybe someone with a 69 Cdn car can chime in.

Heres a pic of my 69 strato chief if that can help

It looks similar to the same year Chevy mirror, except that it appears to have a bigger ball socket and corresponding indentation on the mirror head, plus some sort of screw at the socket (a set screw perhaps?) Those ball-socket mirrors were known for losing the interference fit over time and the mirror head would flop when you closed the door or looked at it. The set screw design looks like an improvement. I had never really looked at them too closely; my impression is that it may be a later GM replacement. What writing is on the glass? It may say something like "DMI" and a date code. That may shed some light.

My Cdn 58 -> 69 parts book lists under group 10.185 that the left side mirror is 9782390 for 1969 ( remember the book only goes to 1969 )
My Cdn 65 -> 76 parts book list under group 10.185 that 9782390 fits 1969 and 1970
My US 70 -> 76 parts book lists under group 10.185 that 9782390 fits 1970 Catalina, Executive and Bonneville ( series 250 and 260 ). Since the book only starts in 1970 it is probably safe to say, based on the CDN book that it will also fit the American 1969 models.

Does your mirror have a part number on the underside of the base?