I bought cab corners, fender bottoms, floors and rocker panels all parts "new" on eBay. Never had a problem with any of them and the price was cheaper. They appeared to be the same gauge thickness as that of the original truck parts. My buddy bought his from a popular retailer in the US (not mentioning any names) and there was no difference in the quality, in fact I would bet they were produced by the same company in China. Have a look if you want.
http://motors.shop.ebay.com/All%20of...5.l1513&_pgn=1