I replace it when I was after Motegi race and I saw in calendar that there are "two Qatars". And after end of a season, I rode two weekend there, so it works without errors - only with some kind of bugs, what I said
About Laguna Seca and Donington - probably yes, if you mean MotoGP14 version of these tracks. Unfortunately I don't have these circuits, so I won't see.
Well, about hex editor... don't changes dots, only letter - so if you have:
...t.e.x.a.s.....
you can change this into:
...q.a.t.a.r.....
You don't have to change amount of signs - it must be constant.