I was going to guess Walthers and Walthers trucks, but it is just a guess. It would have been a kit built by someone.
I don't know what the roof is made of. the Walthers car kits came with wood roofs that were cut square. they used the same stock and just cut to length for a particular car. The modeler had to file and shape the roof ends and add details. The walthers kit instructions came with a template for the shape. This one looks too sloped to my eye to be prototypical. but maybe MKT had some like this.
The modeler tried to make it look like a particular MKT car, so if you can find prototype photos of an MKT baggage car, probably a 70 foot long car, it would be a good guide as to how to restore it.
In my opinion it has little value as a collectible and probably more value as a finished model of a real car.