I am not a nut on authentic consists but I am curious about this one. In 2005 LOTS produced a two car Virginian hopper set and one of the cars had an ETD. Considering, ETDs appear to have started to become common in 1969 (per Wikipedia) and N&W acquired the Virginian in 1959, it seems possible a 100 ton Virginian hopper could have survived for ten years to have an ETD.
OR, did N&W repaint rolling stock quickly after the merger?
Another option, were these cars supposed to be legacy rolling stock and was there ever such a car?