Yep, this is basically a Chevy 150 with some Pontiac lipstick. Compare my door panels to the ones in your Chevy pic...
That is all the goofy Canadian only versions of some cars from the 50's through to the early 70's. There were Canadian only versions of Plymouth, Pontiac and Mercury. Basically the big three's "second line", which gave them a little more variety to sell here. all made in Canada, and were a mixture of parts. For cost reasons most shared assembly lines and a ton of parts.
The American Pontiac is a much bigger car, V8 only and had more in common with the Buick. The Canadian version sits on a Chevy frame, Chevy rear end, Chevy 261 straight 6, shared all glass, doors, seats and interior pieces with the Chevy as well as suspension, brakes etc.
This was all due to trade rules between the US and Canada back then. Any car made in the US and imported here was subject to all sorts of tarriffs, extra duties etc making them very expensive. For the higher end cars like the Buick, Cadillac, and some other models it was no big deal. For the more entry level cars it priced them out of their target market, so the big three created the Canadian only versions of a few brands to increase their brand diversity at the entry level pricing, and built them alongside the more main stream version on the same assembly lines. All Pontiacs except the GTO and Firebird were Chevy powered in Canada. I used to belong to a Canadian Pontiac forum, and there was a documented 1965 Pontiac Parisienne (Catalina) with a stock 409 and 4 speed. Probably one of the last 409's built and installed.