Here is a picture of the black plastic piece.

Strange, I was looking in a VW forum or a DIY write up and their pictures showed not one, but 2 of these on a cam shaft. Mine only had the 1.

Seems to run fine without it and bought new oil cap to make sure it has a good seal in case there is more oil spray up to the cap without this piece in there.

Does anyone have any idea how crutial this part is and should I go back in to put it in there? Also, I would figure that means a new valve cover gasket to, right?

 

I've only ever seen one on Audi's. I don't think it's a big deal if you leave it out honestly I have seen people remove them and not have an issue. As far as if you want to put it back in (I would for the simple fact that I would have nowhere else to put it lol). You don't neccesarily need a new VC gasket as long as you don't break the one that's on there since it is new.