Rule 84, part A looks the same in the 1977 Field Manual.
I agree, the GN 40100-40299 series would be a better choice if one wanted a GN "PS-1" boxcar. Since MT already makes resin load castings, a resin fishbelly add-on would be easy to make, and most buyers wouldn't notice that the car had a "modern" underframe with an old centersill. From the side, on the track, it would look fine.
Given the issues Intermountain has getting their cars to market, I'd like to see MT, or Atlas, or Bluford, make AAR standard boxcars.
Anyone know happened to the Deluxe Innovations cars?