GM Canada used different heaters at least recirculating versions, many I have seen in pictures show GM, not Chevrolet or GMC. That is an aftermarket brand (there were many) most likely readily available or priced right. It almost looks like a bow tie anyway! Here is some additional information for you as to model # and manufacturer.
https://www.flickr.com/photos/advance-design_parts_co/36941614164/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/29272975791/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/25248149898/in/album-72157631868452754/
This is another oddball, not much detail on this one.
https://www.flickr.com/photos/advance-design_parts_co/32593178093/in/album-72157631868452754/

Last edited by Brad Allen; 07/02/2018 3:19 AM.