So far as I know it is legitimate (the car isn't 1:48, though). I could not find a photo of a real one, but Weaver also produced a 1:48 scale model of this boxcar paint scheme - I have it - and Weaver was not prone to fantasy schemes except as custom run jobs.
I do seem to recall seeing a photo of a real one, but it has been a while...
There was indeed a short-lived "script oval" on the NYC in the 60's - it was put on some EMD cab units noses, but I do not think that it was precisely this oval's style.
Anyway, I believe that the car is "accurate". With footnotes.