David is right on the clues concerning the trucks non-originality - the double stake pockets make it a 9' bed I believe, meaning a one ton chassis, but it has 6 bolt wheels [late model wide rims too], meaning a 1/2T axle, which as Cletis points out couldn't have been a longbox, besides which no GM truck will have 6-12" of frame horns sticking out past the tail gate, so the chassis is even too long for the longest box
looks very much like a 1ton flat deck that's been extensively modified sometime by someone, regardless of who the original purchaser was - I'd say if the conversion was well done and it runs and drives it'd be worth 500-1500 to the right person, otherwise it's a parts truck
Bill
