That makes sense on the dining car. Dining car services were contracted services so not all roads used the Pullman Company for those services. I found this on Wikipedia. This might be useful for you. I found it to be very educational.
Eastbound train #38—Advance 20th Century Limited, on February 7, 1930; Sampled at Chicago, Illinois.[10]
- Locomotive: J-1 Class (4-6-4 Hudson) steam locomotive; NYC #5270;
- Class CS Baggage-club car: NYC EAGLE HEIGHTS;
- Class PS Sleeper (14-section): STAR VIEW;
- Class PS Sleeper (8-section 1-drawing room 2-compartment): SPRING GAP;
- Class PS Sleeper (6-compartment 3-drawing room): GLEN ALICE;
- Class DA Dining car: NYC 387;
- Class PS Sleeper (14-section): STAR SPUR;
- Class PS Sleeper (10-section 2-double bedrooms): GANNETT PEAK;
- Class PS Sleeper (8-section 1-drawing room 2-compartments): GLOVER GAP;
- Class PSO Sleeper-Buffet-Lounge-Observation (1-drawing room 1-single bedroom): MOHAWK VALLEY.
Have fun putting together your train!