In the vast, vast majority of cases, no. They are not really belly dancers.
Belly dancers in general have a huge problem with clientele thinking they're sex workers, and the vast majority of them will not entertain the notion of fetish work.
We have a thriving belly dance culture here in the Bay, and over the past ten years I've only ever been able to get one, and she was from Philadelphia.
That's not to say a lot of the escorts and sex workers haven't taken a few classes here and there, but actual pros? No, odds are pretty good they're not doing tickle videos.
Rule of thumb is, nearly anything you hear about the "set up" of a tickling video is 100% fiction.