Here's a link to a DS grade Lefever with a semi-pistol grip stock. See Photo no.5:
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=410892077What you have is what I'd expect to see if the Durstons were building a prototype gun that was a grade lower than the H grade. I'd be very interested to know if the barrels are indeed fluid steel, which would make sense from a cost cutting standpoint. It could be that their original intention was to offer the I grades with the cheaper fluid steel barrels and the DS grade with twist barrels. This might help to explain the DS grades we sometimes see with dolls head twist barrels and cocking indicators.
I would not expect to see any sear adjusters on this gun, and would not even bother looking. I merely brought the appearance of those up to illustrate that sometimes unexpected features appeared on a slightly lower grade gun.