I have 1995 GMC Burb 1500 5.7 6 lug and I have a chance to buy a 1995 GMC burb 2500 5.7 6 lug, or at least that's what the badge/ad says it is. I have not had a chance to actually look at it or check vins or codes in glove box. I was wondering a what is changed from a 1500 to a 2500 with only a...