Darrins could be equipped one of three ways...full size wheel covers borrowed from the 1952-54 Henry J or wire wheel covers with a removable center cap. The wire covers were also used by many other manufacturers as well, a couple that come to mind are Nash and Plymouth. Lastly, on the early Darrins a wire wheel cap with a small spinner was available. Few cars were so equipped and today, fewer have them because they were fragile and easily curb damaged.
Wire wheels themselves, like those pictured in the ad, were purportedly also made available late in the run to use up stock, but I'm not sure that's true. I'm sure someone will chime in with a better answer. In any case, the center caps on the pictured car are incorrect - they're from a Chrysler/Dodge/Plymouth and are much more common than the correct units which are actually modified Henry J poverty caps.
This car has the early style cap on it -
https://www.bonhams.com/auctions/25593/lot/499/The Orlando museum car linked in this thread has the correct HJ wheel cover on it. Note that the filler valve is positioned above the K in the 12 o'clock position. In 1952, the valve position was changed from the 6 o'clock position to the 12 o'clock position because of the 1952 HJ Virginian's continental spare. The filler valve on it needed to be at the 12 o'clock position so the valve position was changed to keep the K upright when the wheel cover was placed on the external spare tire.
