Not at all sure, no! I'm no expert on them.
Below might throw some light on it - it refers to cars built by Ghia rather than Karmann, incl the puzzle car:
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There were two handbuilt prototypes built by Ghia in Turin, Italy, during the year 1954. At that time, Ghia apparently made these two prototypes to explore the possibility of a four-seater sporty Volkswagen Coupe (to potentially have a couple more conservative solutions for Volkswagen to choose from; VW was an exceptionally conservative company at the time). Thankfully, Heinrich Nordhoff either never saw these prototypes, or preferred the original (white) 1953 prototype (which he first saw on 16 November 1953), hence the the car who went into production and became known as the Karmann Ghia greatly resembled the original Ghia prototype.
It's also interesting to note that in 1954, Ghia also prepared two four-seater Cabriolet prototypes, which predated the work done at the Karmann works later (by Johannes Beeskow, none other) to engineer the standard production Coupe into a Cabriolet form. One of these four-seater Cabriolets was a light beige color, the other a dark hue.
I don't believe any of these four Ghia-built 1954 prototypes still exist today; only the original 1953 Coupe
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The picture below is NOT the same car as the puzzle car, but maybe they're both developments of the four mentioned above that no longer exist? The 1955 plate might be confusing; it was probably made in '54 as a proposal for '55?
