Magazine Release Spring

The spring popped out when I removed the left grip. Which side of the spring should face the grip? The convex or concave? I assume it's the concave because the little tit at the end of that side of the spring apparently fits into a small semi-circle cut into the little slot on the frame; but I want to make sure. Also, is the spring numbered? Mine is not. Thanks. Ad.

My provider disconnected while I was posting and I didn't realize the posting had gone through when I re-connected and reposted. Ad