AMS is Accucraf't's specific branding for their Fn3/1:20.3 offerings. Their J&S car range was produced in both plastic and brass, Those included in the standard plastic range were either all chair or a combine configurations. The brass range was to offer a replication of the San Juan set. Their cars were both longer, in nearly all instances, with more veriety and some with enclosed vestibule ends that included a veranda ended parlor car, The range encompassed the D&RGW, RGS & C&S variants of these cars where applicable. Red oxide, Pullman green and the Yellow "Bumble Bee" liveries were available, again as offered on the prototypes.
Rio Grande Models (UK) offered a very neat laser cut wood based "transkit" for the plastic cars to make a very nice "Pagosa" combine. Oft replicated, but in very reduced size form, by other makers and marketed as a "drovers' caboose".
A lot of the C&S liveried examples have ended up as kit bashes to some other D&RGW variant. Not popular they could be picked up at reasonable cost in "close out sales" or 2nd hand a few years ago. They do come up occasionally now, similarly marked down over the more popular D&RGW and RGS variants. I bought one from Garden Railway Centres some years ago, NIB but fitted with ball bearing wheel sets (std plastic are plain bearings, brass ball, bearings) for £140. I converted that to the "Pagosa" combine configuration. The difference in rolling resistance between a car running on plain bearings, with its lighting pick up wipers, and ball bearing examples, with axle mounted pick ups, is quite marked. Max