i was playing 2 players on the pillar of autum and i look at emile he has no skull on his helmet so i staterted recording if you want to watch it heres the link
http://youtu.be/bL5xCKP6f94
i created it i used a phone so black lines pop during the video sorry didnt use my camera but hope you enjoy it
Reach’s graphics engine is almost too much for the Xbox to handle. When you’re playing two-player split-screen, you’re essentially running two of the graphics engine. To avoid overworking your Xbox, Reach tones things down and removes a lot of details – the skull on Emile’s helmet being one such detail.
The removing of details is unfortunate, and can cause some problems (especially in Forge maps), but it’s either that or melting your Xbox. 
Hope this helps, mate, and welcome to Waypoint. 