Ben -
The description on the FAQ brings a picture of an opened side which "allows the blade to be drawn from the back of the scabbard". Terry Sisco's quick draw scabbard was open on the spine-side (front, to me) of the scabbard, from the bend to the top, with a snapped thumb-break strap to secure the blade. The belt loop was sewn to the leather (or was part of the leather) wrapping the scabbard, and not on a frog. The pic isn't clear enough, but there appears to be what might be a release on the strap on the fitted sheath. This may have been the grandaddy of the clamshell holster.