Well… Marilyn found a book at the Chicago Public Library it is called VW Camper - The Inside Story by David Eccles. This comprehensive book helped us sort out the Westfalia from the Sundial to a Riveria.
From that book we learned . . . .
In 1951 Westfalia introduced the first VW camper. This camper had removable parts that could be used in the home for house guests! By 1955, Westfalia was producing fully converted buses and in 1959 brought the SO23 to market.
Other companies that were also doing the bus conversions were Devon (1957), Moortown (1958), Dormobile (1961), and finally the Danbury (1964). One thing we found interesting is that during the 60’s only Devon, Dormobile, Danbury, and Westfalia were officially recognized by VW. Other conversion companies had separate warranties.
In the 1960’s, the popularity of the Westfalia out sold the supply in North America. This led to other conversion companies entering the VW camper market such as EZ Campers, Sundial, Riveria, and Road Runner. These companies based their designs off of the Westfalia interiors.
EZ Campers began converting panel vans in 1963/64. There is also a webpage that out lines the history of the EZ Camper that is quite informative. This fellow even has replacement ID tags for your conversion. One of the models, the El Viajero looked very similar to the Sundial, however, the EZ was more luxurious. The 1965 EZ was based on the Kombi. This conversion featured 6 “pop-out” windows and birch panels instead of the EZ grooved style panel
Riviera / ASI

This dealership in Beaverton Oregon partnered with ASI (Automotive Services, Inc) in Vancouver Washington in 1965 to product a VW conversion to help offset the tight supply of Westfalia buses. These buses were .. just like te EZ Campers, based on the Westfalia. Since there are no serial numbers on these conversions it is unknown how many were produced. Most of the buses produced by this partnership were walkthrough panel vans. ASI also allowed customers to bring in their own buses for conversion, which would explain Riviera’s that are pre-1965. One of the obvious characteristics of these buses were the long “picture window” in either a slider or jalousie. The single windows were different that the Sundial and the EZ in that they were sliders instead of flipping open. The interiors were made from lightly stained birchwood. Some of these buses came with “pop-tops” from Sportsmobile in Elkhart Indiana. The Riviera Registry has more information on pre-1968 buses
I appreciate the link to the Riviera Registry, but remember it’s spelled “Riviera” not “Riveria”.