Walthers made the PRR R50b express refrigerator car, which is quite a different car. Walthers also made the PRR B60b baggage car, which also is quite a different car.
The similarity in car type numbers makes it "interesting" when searching for information about the R60 express refrigerator car, of which PRR only had 36 of them. PRR had hundreds of the other two cars. Initially, I made the same assumption that you did.
I suspect that my best hope is to find that at least one of the R60 cars got re-trucked with a more common PRR truck. The 2D3P1 truck may be unique to the R60 car.