It looks like someone will now have to find out if that really is the custom or not.
It is. But the registration among other things also sets forth the place of birth.
I wouldn't view it as "dirty tricks" operatives to investigate facts regarding the eligibility of the opposing candidate. And further, from what I know, I don't think the operatives were dispatched by the Republicans either.
If my informed guess is correct, the investigators were hired by an offshore political entity that views Obama as a threat.
Information about what they found is in the hands of several parties in Washington DC including the Republicans. So far, there isn't any information out there as to what they intend to do about it.
Well, every year we are told there will be an October Surprise, maybe this will be the year. Not holding my breath