For the most part today, due in large part to modern machinery, pistons are much more consistent to a given bore size than in the past. As for forgings, the bore size is the same, the piston is actually a little 'smaller'.
Agreed, if it "measures" correct, it's good. Ask if it was honed with a deck plate. 350s really should be for any application. If not, negotiate a lower price and bore it to .040" over. Pistons are readily available in virtually all configurations and are the same price.