While not the Lionel cataloged baggage car, perhaps some will find additional info on the car in photo above of interest. The green REA lettered car in the photo is a former PRR Horse express car. The railroad's Altoona Car Shops built 25 class B74b horse cars in 1928. In PRR service they carried distinctive horse racing related car names. One end had a diaphragm protected door, while the other had double end doors for ramp loading/unloading. The PRR also had 45 similar 2 doors /side (one double, one single) B70a baggage cars outfitted to handle theatrical scenery. They were named after plays, playwrights, and actors. When not needed to move horses or stage materials the cars served in the Railway Express Agency baggage car pool. For more info and pictures see Pennsylvania Baggage & Mail Cars by Robert Liljestrand & David Sweetland. With the exception of car names for most of their service lives they were painted and lettered in standard PRR baggage car livery.
Unpainted brass models of these prototypes were imported by Sunset (Mort Mann) from Japan in the early 1980's and more recently painted ones from China by Sunset Third Rail (Scott Mann). Below are photos of the Sunset models I've been running in PRR mail and express trains for over 30 years.