im looking at a 86 gmc short bed truck. it has 33 inch tires. 4wd. 350 motor. would it be a 1/2 ton or a 3/4 ton? ive heard they made both in thos years but how do you tell from the outside if there a 3/4 or a 1/2? it dont say 1500 or 2500. or c10, c20. thanks, any info is apprecatied