The prototype is discussed in the Rolling Stock Reference Series – Volume Seven, Santa Fe Open-Top Cars, pages 256, 261-263. General American built 75 covered hoppers class Ga-58 in 1942. These were cement hoppers. In 1946, an additional 250 cars class Ga-65 were delivered that were exact duplicates except for the trucks. The Ga-58 had Barber Stabilized S-2 trucks while the Ga-65 had ASF A-3 trucks.
More details on the Prototype can be found in the Railway Prototype Cyclopedia, Vol. 27 & especially Vol. 28.
The Bowser car, however, has the V cutout in the side which matches the earlier Ga-52. The Ga-52s were 1958 cu. ft. cars from General American built after the AC&F design. The Ga-52s had Barber Stabilized S-2 trucks and Apex steel grid running boards. Therefore the Bowser models should be Ga-52, not Ga-58 and with appropriate numbers for the Ga-52 instead of numbers for the Ga-58. Intermountain has done a more detailed Ga-52 in their 1958 Cu. Ft. 2-Bay Hopper – Open Sides series.
The Bowser car came as a kit when the reviewer purchased his. It is a more basic car than the Intermountain with molded grabs and more limited brake gear. The Bower has a full width coupler box. However, using the 3’ rule, it would be difficult to tell them apart. The car weighs 3.25 oz, just short of the NMRA 3.5 oz standard.
Thanks to Steve Sandifer for the review and photographs.