It seems like these aren't Noahides so much as gentiles acting like Orthodox Jews. Noahide laws don't require kippahs and beards etc...
Wearing a kippah (or some other hat) shows respect for G-d. An uncovered head is a sign of brazenness. And as for the beard, there is no prohibition on having one. In fact, that is the preferred way, just as Noachides aren't forbidden to cremate their dead but it is preferred that they be buried in the ground.
It takes a lot more than a kippah and beard to "act like an Orthodox Jew."
The Torah talks about not shaving the four corners of your beard. This, along with the prohibition on mixing wool with linen, has always struck me as something that meant something very different at the time. Back then virtually all men wore beards. Those who did not were probably members of some local cult.