Look at the in-game screenshots on the back covers of the C64 releases. They're weird. One looks like it's from Amiga Test Drive II, it's okay, but I don't remember that sign in it. The other is on the back of the cassette keep case. "These screen shots represent Amiga version" but no! It looks a bit even more advanced than the Amiga version. Is that a screenshot from a prototype version maybe?
I don't see anything unusual. Looks like a CRT camera snap.
It definitely looks fishy. A mistakenly added screenshot of TD2 on the box of TD could happen, if that edition of TD was released later. But the fact that it contains elements that are not even in the final TD2 seems to suggest that an unfinished prototype was shot, or that it is a blatant case of screenshot manipulation.