A GMC 1/2 ton 4x4 will be a K15. GMC used a slightly different numbering system that Chevy,with the numbers ending with 5 instead of 0. Where the Chevy would be a 10, 20, 30, the GMC would be 15, 25, 35 for the same range truck, The only exeption was the Jimmy, which was a K5 just like the Blazer. I'd say somewhere along the line, the truck got titled wrong, easy mistake to make.
