Does that kind of numbering style have a common name or names? To be fair, it is really more of an "identifier" since it certainly not a scalar (one-dimensional) number. It isn't fair to call it a floating point number either.
If I were to hazard two guesses, I would say:
- a document identifier (but that seems so vague)
- a multi-dotted number (silly, yes, but it gets the points across)
So in reality, I've got nothing.