My Weaver GM&O chip hopper. Early dry-brush weathering job; OK, but I use Bragdon's dry pigments now for better and more controllable results. This is the original Weaver lettering and "wood chip load" (real wood!).
I grew up seeing these things; all were black - and all were rusty, which can look brown/red, of course. I didn't see every one, naturally, but I never saw a brown one.
These are nice cars - and got so expensive, even in a no-truck kit form (which this one was when I bought it years ago) that I just refused to pay the price even when they showed up on eBay.