Rail Craft made several different O scale car kits with tinplated stamped steel parts before WW II. They were sold less trucks and couplers, so finding an old kit-built car like that could have such period parts on it. Rail Craft also sold cars built up, ready for trucks, couplers, paint and lettering.
Henry Beeson, I think, was the producer of this line of cars and kits. Not sue if this is really so, but I've read that he was a high school metal shop teacher and often had students involved in making the parts and sometimes completing finished cars to sell as well.
I had one of them, this panel side two bay hopper, which is 17/64" to the foot scale, which was done by other kit makers as well in the late 1930's. I have three other Rail Crafts, two kits and a not so well-built car to work on someday. One kit is a panel side gondola. The other is a B&O experimental "More Service" flat car, which could be made into a gondola by means of raising up drop end and side panels that folded down into the car deck. The last is a USRA rib side twin hopper that needs to be redone as some parts were not correctly located when soldered in place.
The Rail Craft cars tend to be light in weight when done and are usually made from tin can stock. Using a magnet is a big help in determining if steel was used in their construction. It can help identify box cars by Athearn (and the later producers of that line) from General Models / All Nation box cars. Athearn used steel, GM and AN used sheet aluminum, which is non-magnetic.
Below are the Rail Craft panel side hopper and two other steel cars I am working on that date from before WW II. The hopper is a USRA rib side twin hopper made with thicker steel than Rail Craft used. It scales at 17/64" to the foot and weighs 2 oz less than a pound. The tank car has a Walthers under frame and dome, but all else is steel. The tank measures at an 11,000--gallon capacity. Walthers wood tank car body kits mainly of the 8,000-gallon size. I added missing parts in brass as well as a detailed brake system underneath.
S. Islander