Jeff can answer this I'm sure, but looking at enlargements of my photos that I took of the car as it sat in Iowa last fall show the brake staff mounted on the corner of the car end with one side/corner stake and the wrap around bracket holding up the brake staff and wheel.....I probably should have posted the picture I took from the B end. Sorry for the fuzziness, had to crop and enlarge the original to get under the 1.2mb picture limit.
For what its worth it would be interesting to know the D&RGW car number............