Clark Propst wrote

The Walthers car has a oval hole in one side, the Tichy doesn't. I'm hoping
the Tichy car resembles the earlier Santa Fe cars?

Clark, I think the two models represent the same version of the GSC flat. (There
were other GSC castings with a thinner profile, but that's another story.) The
hole cast into the side was for the brake release rod. (But why wouldn't there
be a hole on each side?) Other flat cars have them too, but with those the builder
just cut or punched a small hole in the side. With cast steel, you can't do that
very easily! I think the Walthers is a better model in general, and definitely is
better for kitbashing bulkhead or TOFC versions.

Tim O'Connor