I've shot both an AK-47 and an AK-74 semi-auto left-handed, never had a problem getting hit by brass.
Watch out for the slant brakes they put on a lot of them, though. They'll be set up for right handed people, but in my experience, rifles recoil differently for southpaws than they do for righties. For right-handed people, the gun tends to go up and to the right. The slant brake is designed to push the gun down and to the left. Shooting left-handed, I've noticed that guns tend to recoil straight up. The slant brake will still push down and left, so when it comes back down level with your target, it will be way off to the left, and you'll have to drag it back over.
You can either get a gun without a slant brake (no brake at all is fine, really), find a slant brake that can be set for either right or left-handed people (I've seen them, but just don't care for them), or replace the slant brake with another style of brake (AK-74 style brakes are fairly easy to find for the '47s and make the gun look better to boot, IMO).