At first glance, I thought it was one of the old Train Miniature (now Walthers) versions of the USRA doublesheathed boxcar. While the TM car was a good-looking model, it was not the correct height (too low). Your car has a similar type of door tracks, and the "nubs" visible inside the doorway on the underside of the roof are the same as the TM car. What
is different is the roof: while your car has 11 panels, the TM cars had twelve. Here's a picture of one of three that I rebuilt to match some prototype photos.
My cars include reworked sides (to add the "missing" height), new doors, ends, roofwalk, and underbody, along with new brake gear and metal steps and grabs.
Hopefully, Ray Marinaccio will check in here, as he'll likely know the origin of your model.
Wayne