Yes, in certain cases "to" acts as a proper preposition and not part of an infinitive verb. "To be/get used to _ing" is one of these cases.
If you want to check if you really need _ing for the verb, try putting a noun after "to". If the sentence still makes sense, then you need a gerund (_ing) form.
Australians are used to [different road rules].
Lisa has got used to [a German lifestyle].
I'm used to [hot weather].
I can't get used to [the noise].