You bring up a valid point, and it was discussed at length before I started the build. The short of it resulted in that they would be easier to fill after the fact then to cut them in if we decided that we wanted them.
As to what I am planning to do on my costume, I'm going to have them. The clone wars series uses a very stylized helmet for the Death Watch guys. The critical point for me was that they did show the Jango Fett helmet in one episode and it was the same stylized helmet that the Death Watch guys were using (although it did show the turn signals). As I'm looking to build a Death Watch uniform/armor that looks like it was from one of the movies and not the cartoon, I figure that every movie mandalorian helmet had these, so why wouldn't these ones.
I looked into the 501st requirements a bit as well and it looks like they require animated style helmets. As I'm aiming for a movie style helmet of the animated character, these will not likely qualify for use with the 501st without some modification. While the turn signals will be easy to fill, I shaped the visor very much like the movie helmets and not the animated series. This will not likely be an easy modification. Of course if they include death watch guys in the upcoming Boba Fett movie, I just might be ahead of the game for once.
