As I remember, the very first of the Model A's (Oct.,Nov.,Dec. 1927) used a continuation of the Model T hubcaps of the '26 & '27 wire wheels. You can look at the photo (MAC'S online has the best photo of one) and description in Snyder's Catalog, page T-27. Snyder's reproductions of the '27 'T' hubcap has an octagon frame at the top, otherwise, it is very much the same as the very early '28 hubcaps of the '27 period.
This is an observation of an old man, who long ago sold his wire-wheeled '27 Model T , so take this information as a starting point in your investigation - NOT gospel truth !
- Doug Vieyra, Eureka, Calif - Sunny and 65 degrees . . . . again