I also have a left handed Stag upper.
However, the only time I've had brass in the face was a highly sporterized AR that did not have the brass shell deflector and the ejection port had been milled back to make it longer (for a new charging handle attached t directly to the bolt carrier). Even with the older A-1 receivers I've never had brass in the face.
The right handed AR with brass deflector can be very friendly. Add an ambidextrous safety and a Norgon (there are others but Norgon is standard issue on Canadian AR issued military guns) magazine release and you should be good to go.
Vigilantibus et non dormientibus jura subveniunt. Molon Labe!