It doesn't mean anything other than that they're all products of Bosch.
That doesn't mean that they're all the same; but it doesn't mean that any of them are different, either.
If I had to guess, then I'd guess that there are differences. There's a lot of variables that go into the design of a saw blade.
(Googles)
Well who knew? Bosch own Freud. Does that mean Bosch saw blades are also Diablo/Freud, just in Bosch blue? There's so many different variants, and they change over time, that a straight D vs. B visual comparison isn't really possible.