I'm thumbing through my Winchester catalogues, and the 16-gauge Model 12 Skeet Gun disappears between the 1951 and an October 1952 catalogue. In 1954 the "Winchester Special Ventilated Rib" (Simmons Rib) became available on the 12-, 20-, and 28-gauge Model 12 Skeet guns. Prior to that only the 12-gauge Model 12 Skeet Gun was offered with the real "Winchester Ventilated Rib", while the 12-, 16-, 20-, and 28-gauge Skeet Guns came with a solid rib. In the January 1955 one could still get the solid rib Model 12 Skeet Gun in 12-, 20- or 28-gauge, In the large 1955 Winchester catalogue one could get the newly offered Super Field in 16-gauge with a solid rib and skeet choke, but the skeet choke offering in the Super Field is gone by the revised to September 1955 catalogue. In the big 1955 catalogue the Model 12 Skeet Gun was only offered in 12-, 20-, and 28-gauge with the "Winchester Special Ventilated Rib."
Prior to WW-II, one could get a 12-, 16-, or 20-gauge Model 12 Skeet Gun with a plain barrel and a Cutts Compensator attached. The Cutts body could be blued steel, aluminium alloy bright or aluminium alloy blacked. Post WW-II from 1946 to 1954, one could get a 12-gauge Model 12 Skeet Gun with a plain barrel with a forged shoulder on the end that was threaded and the Cutts body screwed onto this shoulder. I don't find smaller gauge Cutts offered after the War, and I don't ever find the Cutts offered on a ribbed barrel either solid or vent. That said, Riffle shows on page 139 a Model 12 28-gauge Winchester Special vent rib, factory Cutts equipped Pigeon Grade, and on page 168 a 16-gauge Pigeon Grade with a Winchester Special Ventilated rib and a Cutts
