Just for the record, the Soo Line Historical Society does show a red lettered boxcar. I guess they did this in 1977.
http://www.sooline.org/publications/drawings/cars/1977xm.gif
Of course the real cars were pretty much all built in the SOO's shops, so either way the Athearn car is still a fantasy. The only way to be 100% accurate would be with the Modeler's Choice styrene car side kit, which would be a heck of a lot more work than this though.
Other than the lower side sills, the SOO cars are similar to ACF built cars; ACF probably provided the kits they used. I know people have been using Accurail ACF boxcars as stand-ins for years (these days Atlas would be a better choice); the SOO historical society was selling custom decorated runs of the Accurail car for a long time.
Just sayin'. The weathering job on the model looks pretty good, independent of whether or not it's actually the right car type. I'm just a stickler for these things. I like the subtle differences.
