Shavano upgrade

I've recently come across some photos of open-platform passenger cars in Montrose and Salida in 1940. One of them (285) is freshly shopped, while the other (290) looks within a year of being shopped. (An interior shot of 285 shows it still had gas lighting.)

This struck me as odd as the Shavano came into being in 1937, supposedly with vestibule cars, electric lights and air-conditioning. So what were freshly shopped open platform cars doing in Montrose and Salida in 1940? Were they still running both style cars? Were they running "other" passenger trains on a different schedule to the Shavano? Was the RMRRC (only 2 years old at the time) big enough that the D&RGW would keep these around (and freshly maintained) just for excursion trains?

Any insight appreciated.

Cheers,
Jeff.