I looked into the books:
The observations of the 20th Century Ltd before 1938 where all of the Valley class an all lettered Pullman (according to Some Classic Trains (Arthur Dubin) and 20thCentury Limited (Karl Zimmermann)). The restaurants were lettered New York Central. The club baggage was also Pullman lettered. My 1 gauge Century is supposed to be correct:
Regards
Fred