I read somewhere one time that the Canadian General Motors has even more information.. or more specific to your exact truck information than the US division... maybe they kept better records or something.
Anyway, I'm pretty sure they have the restoration packs up there also.
Another thing to try, go to the link below and look for the Parts Vendors that say 'Canada' on them... I think there are 2 or 3 linked in the list... I'm sure they could point you in the right direction or help you out.
http://woogeroo.home.mindspring.com/autolinks/trucks/ctgparts.html I hope this helps.
Also, be sure to check out the links page here at the 'bolt.
-W
