I guess if you have someone carry your longarm from you to shoot then you wouldn't need the swivels. When hunting I consider the sling, i.e. sling swivels, a necessity. But the cocking indicators didn't last too much past WWII. Sauer had planned to introduce a pop-out indicator at the 1937 German Hunting Exhibition, but pre-WWII examples haven't surfaced. But MEWA and Thalmann as well as Sauer Eckernford doubles did take advantage of the technology on post WWII models. Regarding the "clock-hand" indicators on doubles, I don't think they were used post WWI and with the drillings using a "clock-hand" indicator, or other cocking indicator, up to and possibly thru the mid 1930s.

Kind Regards,