If you are looking for touch up paint, that's an entirely different issue than getting a paint code mixed up for you so I am not sure what you need the paint for??
Call a paint jobber store in Canada if you've already tried calling one in your state. Either one might be able to tell you if they can mix it for you in a single stage urethane. Failing that, find an area that you believe to be the original color that hasn't been exposed to the elements and have a local paint store tint to match. Don't rely on any camera as the final result because it won't be the same color. The camera only gives a (good) tinter a place to start a custom tint. Once they have it figured out, they can make as much paint as you want. Even if you have to take the door or hood in, that's the best way to get the same color.
Another option is to contact
Vintage Vehicle Services as they recorded much information on Canadian made GM products, including how many were manufactured, where they were sold, paint codes etc. I can't vouch for your truck, but I was pleased with their intel on my 1959 GMC that 2697 were made.
