The commercial M-S should have the bolt stop spring at the area between the bolt handle and the action opening. As far as bbl. length, from Max Chittick book M-S 1903 in 6.5x54 was offered only in 6.5x54 and three versions,a carbine w/ 17.7" bbl, sporter half stock w/23.5" bbl.,and the takedown model w/23.5" bbl. All three were offered w/ DST or ST. All models were equipped w/ a sheared bead on a bbl. band front sight and 2 blade(1standing-1 folding) rear sight.
Bob