There is no 993 Speedster that should not exist, but at least two of them are officially made by PORSCHE. One was a gift given to Ferdinand Porsche on his 60th birthday (now the Porsche Museum), and the other was sold. The base is a narrow body Carrera 2 cabriolet, the exterior color is green meta, the interior is RS sheet, TIPTRONIC with dark brown genuine leather specification using wood trim. The front screen seems to use 964.
After that, it seems that several 993 Carrera S-based Speedsters were also made, but I do not know how good this can be said to be genuine.