welcome to the shop Rob, good choice to switch to trucks

price sounds fair - for rust, look carefully at the lower hinge pockets [and behind them, under the fender] and the cab corners from
inside, as well as the door bottoms, although being a dry area truck rust may well not be an issue .... for the V8 being original, in 57 a light truck would have had the 265, not a 283, check if the front mount frame pads are riveted on [original] or bolted [added later] .... it could be a 265 he thinks is a 283, or could be a replacement
Bill