Just thought I'd comment on another similar car I came across. I was thumbing through the BN Color Guide to Freight and Passenger Equipment by David G. Casdorph and on page 45 it shows an ex-Frisco Magor car that looks very close to this Milwaukee car. A quick job would be to remove the Milwaukee Road lettering, reporting marks, and road numbers and replace with BN reporting marks and numbers. (there was no logo on the car in the book, just B N reporting marks and 439 514 for the number.) From the book, the BN series is 439500-439599. I'm still gonna do a little more research to see if these were in captive service or otherwise what they were used for. (mainly, were they used for standard grain service and/or did they commonly show up in Texas)
Obviously, it could make for an interesting Frisco car as well, although there is absolutely no trace of any Frisco logo so it would be interesting to see what it looked like as an SLSF car. (the series, again from the Casdorph BN Color Guide, is 86000-86099)
Any suggestions about the best way to remove the black MT lettering without jacking with the aluminum finish?