Scamp Casita and the earlier Escapes used the narrow 21" W refrigerators. Scamp and Escape used the Dometic top vents. Casita and Scamp 16's on some trailers used side wall upper vents and those trailers are more prone to have Frig. cooling issues more so than the top vent trailers
The Scamps I have owned used the roof Dometic Frig. vent cap. It is not usually stocked in a lot of Rv Parts stores for some reason. Does your vent look like this? https://www.rvpartsnation.com/rv-appliances/rv-refrigerator/rv-refrigera... . I think this is just the cap.
Scamp Casita and the earlier Escapes used the narrow 21" W refrigerators. Scamp and Escape used the Dometic top vents. Casita and Scamp 16's on some trailers used side wall upper vents and those trailers are more prone to have Frig. cooling issues more so than the top vent trailers
Eddie