I have three of the previously offered M-K-T single sheathed box car kits available – link here. They are for the version with the National doors and Pressed Steel roof. Caveat: I only have the white decals for a box car red car (pre-1938 and 1948 and later repaints). Photo above shows the car offered, but finished with the black lettering. I am reprinting the decals for the black lettering on chrome yellow cars and will gladly mail you a set once they are complete if you purchase a kit and want that lettering – just let me know!)
These are the only three available currently and I do not have an estimated date on a restock.