If you are referring to non-GSX vehicles, those that wanders around the airport and service AIs or your airplane if you don't use GSX, which are called Living World and Airport Services, we surely have Turkish vehicles correctly assigned by-airport, using the Airport Services files.
Of course, that assumes you haven't disabled them (perhaps to speed up loading times), because if you have, their assignment will be less accurate "by region" instead of "by airport" and, as you can see from the map included in the manual you quoted, Turkey is in the overall J region, so you'll get a random selection of all sort of middle-eastern operators, which are many, so your change to see Turkish vehicles will be lower, just because there are many other operators to compete against.
Now, there's the notable exception of LTFM. Since there's no LTFM in the default MSFS scenery, we don't have a custom Airport Services file for it, so *there* you will ALWAYS get the less accurate "by region" operator selection for ground vehicles not operated by GSX.