Chris is correct on all fronts. The NPS gave the D&S bad instructions. My guess is that they used a lettering diagram for a standard gauge car. The end lettering on 3132, while correct in font and content is TOO BIG, there is just no way around it and more than enough physical evidence (in the form of numerous period photos showing the small lettering as seen above, compared to EXACTLY 0 period photos showing the large lettering applied to 3132) to prove this fact beyond a reasonable doubt.
Clearly, the NPS researcher was not thorough enough in their work, probably not well versed in the nuances of railroad practices, found an "official document" and ran with that over the "railfan photos" that overwhelmingly show that the larger lettering was not used on 3000 series boxcars. My bet is that the folks at the D&S who did the work were well aware of the issue but caught in a "the customer is always right, even when what the customer wants is wrong" situation.
The D&SNG's work on 3132 was exquisite, the car is a masterpiece until you see the end, every detail is spot on correct, save that damn oversize end lettering. My non-railfan nephew even noticed that it looked out of place and asked me if it was done right when we stopped by Cimarron a couple weeks ago. It is not the end of the world, but it is a bummer that such an easily solveable error was not allowed to be corrected before the car went on display. Given the level of research and that work went into getting all of the details correct, along with the level of success that was achieved, there is no excuse for not fixing the error. As with many things, there is no shame in the error, just the refusal to acknowledge it.
Should anyone come up with a period photo showing the oversize lettering in actual use, I will take back my statements.
Jason Midyette