If you are saying Lefevers are not all that common in 20ga you are totally correct. It does seem though that the most commonly seen 20ga is the DS. The DS is the Durston Special, & normally lacks the Doll's Head on the rib extension, the cocking indicators as well as the forend tip & escutchion in the center of forend.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra