Mexican Sleeper/Business Car Interior

Many of us are familiar with Mexican rolling stock. Although I was aware of the Pullman sleepers that ran on the Rio Grande being transferred to Mexico, some other Pullmans have remained a mystery to me. One such narrow gauge car, is the one pictured in Saltillo in the Gerald M. Best book "Mexican Narrow Gauge". I've looked through this book in the past but couldn't find much information on the car. I've provided the link to Amazon and the specific page. The car I'm referring to is in the bottom left corner. Although the caption says this was the CyZ business car, the window arrangement says it was a sleeper, at least at one time. There are no interior pictures or blueprints given. So I'm wondering if this car has a similar berth section layout like the tourist cars inherited from the Pullman Rio Grande operation? And what was the disposition of this car? Do other examples exist?

[m.media-amazon.com]