Here's pix of the Weaver ones that we still have a few left in stock. The Lionel ones are the same, just different road names. The Original Weaver ones were done in the late 1980's, afaik, and they were kits where u had to put on the trucks and couplers (NBD, obviously), but the extended sides came as separate pieces, and u had to glue them on. I have a few old the old ones built up here, with actual woodchip loads that someone went to all the trouble to do, and about a dozen of the original kits, unbuilt. I dont put the old kits up for sale cause who would want to have to put them together.
Atlas also did some 40' 3 bay hoppers in woodchip livery.