So is the blizzard over yet?
I am curious as to what year your truck is. I have not seen production numbers, but I seem to see 2 59's restored for every 58.
In case you head south across the border for parts Canadian GMC's and US GMC's do have some differences. Basically a Canadian GMC has Chevrolet running gear, where as a US GMC different engines etc. In Canada the six cylinder would be a 235, and the V8 a 283, but in the US the six is a 270 and the V8 is a 336.
Best of luck with your truck.