Well, that may be. Unfortunately I'm much less familiar with colloquial German in countries other than Germany... Which is to say... well, that's a weird statement because formal German seems very uniform across the lands (apart from some small spelling differences).

Oh, also Grüß dich isn't particularly regional, I would think, becase grüß is simply the imperative form of the pretty normal verb grüßen - to greet (probably a cognate too).