That is the common direction. However, If you don't know it's history then study the area and see it you can tell when direction was last used. I have seen some installed in the opposite direction. You can tell a lot by looking for signs that somebody left for you to read. A friend of mine once showed me his Grandfathers old SXS shotgun. I asked him is his Grandfather was let handed. His looked surprised how I knew. Pretty obvious. …..I've read that as you stand behind the weapon, drift it LEFT to RIGHT?