If the studs look like they have about an extra 1/4 inch too much length for nothing it’s a dual rear wheel axle
If the studs stick out from the nuts just nice then it’s a single rear wheel axle
That’s the only difference
The ratio is 5.13 about as that’s the only option for a 1 ton and you mentioned it came from SK so it likely is all original as no one had two pennys to make modification to the trucks in that province and the 3/4 ton is much rarer to find in SK which would be the only source for a lower ratio axle
Your other photos show it has the auxiliary spring package which means it was meant to haul a lot of weight.
-s