I'm a lefty. If I were buying a bolt action I wouldn't buy a LH model. If I were buying a DI AR style I would buy it LH. They expel a good amount gas out from the bcg and with a lefty using a RH rifle that is RIGHT in your face. Needless to say if you're looking at the model 8 (piston driven) I might not rush to get it LH. It's a few dollars more for an LH model and you bet you can spend that $$ more wisely (read as ammo, optics, other "needed" accessories).
I thought and thought about this when I was shopping my AR. I ended up with a PWS, which is a long stroke piston driven AR, there's a little bit of gases that you deal with but the bulk is expelled out the gas block. I added a Magpul BAD and i'm good to go. The shells NEVER hit me (well at least not in the face) as they're extracted and it's a bad *** rifle. Would a lefty version have been better? Maybe, but PWS doesn't make one only a small handful of manufacturers make a dedicated LH AR. And I don't k ow if I would have paid the up charge for it (usually its 10-15% more for a LH model).
Bottom line, for a DI rifle IMO its worth it to get the LH for a piston drive, not so much. Worst case is with a LH model you can tell your Friends they cant mess with it cuz they're righties.