Any 1952 Kaiser convertibles built were done as custom jobs by body shops (the Henry J was the car of choice for this kind of thing) or by an owner somewhere over the years. There was a body shop in Minnesota that worked with Irving English, the Minneapolis MN K-F distributor (he owned Northwest Kaiser-Frazer) and the factory features one of the cars in the December 31 1951 issue of KAISER-FRAZER DEALER NEWS and suggested interested dealers contact Mr. English direct for more info. Somne 1952 Virginians (the re-tagged 1951 Kaiser bodies with two-piece windshiehd, etc) may have been rolled out by this shop as convertibles. However these cars were not factory engineered or styled.
Documentation wise, if you found a 1952 Kaiser convertible, it would start with a body tag that showed 999 for Paint, 888 for Trim and have a number starting with K- at the SPEC-FO header if it was a factory job.