If that GMC has 150 labels on the hood, then it's a '51 DeLuxe Cab 3/4 ton. Measure the wheelbase and see if it's 125.25" and if there are 8 lug rims under those hubcaps. If yes, then you have yourself quite a score. The hubcaps alone are worth what you paid for the whole truck...if it's a 3/4 ton. Also, do the doors have stainless steel trim inside and out around the windows? Stainless trim around the windshield? Four speed?