The value of Matchbox cars usually boils down to a few things: the condition of the vehicle, whether you have the original box it came in, the production year made, and any variants it might exhibit (i.e., reversed colors, factory errors, color variations, limited run, etc.).
In 1966, Lensey released a 230 SL Mercedes-Benz (series 27d) with a white body and red interior. This was converted to a white Superfast edition (again with red seats) in 1970. The following year (1971), it came out with a yellow body (keeping the red seats), but later that year changed over to a black interior. Again, these cars in and of themselves aren’t worth much.
But then there’s the mystery of the apple-green body with a red interior. Oddly, this color variant isn’t on any official Matchbox list of released vehicles, and even the scale is up for debate, with some sources claiming it a 1:60 while others 1:75. Virtually nothing else is known about it, including how it came to be or how many were released. It has since been pegged as a 1967 prototype or pre-production model.
What is known is that in 1999, it sold for $6,765 and has not been seen in public since.