Welcome to the site. Looks like a nice car that you have there. I also have a 1980 factory 4 speed/305 Malibu, which is an Oshawa built car, another one of the 124 built for Canada that year. I was fortunate that the person that I bought the car from, turned over the original dealer invoice to the original owner when I bought the car from him. If you're looking for documentation, look up Vintage Vehicle Services in Oshawa Ontario. For a fee, they will send you documentation on your car, as long as it was originally titled and sold in Canada.
They can provide build date, assembly plant, original shipping dealer, all of the RPO codes for all of the original options that the car was built with, as well as some other info on the car. I've found that short of having an original invoice, or build sheet, this is the best way to go.
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