JRH6856
Member
My Standard made in 1976 has the thumb stud on the left. 9 round mag. But the stud can be moved to the right side for use on the older frame.the earliest mk guns had the thumb stud on the right side of the mag. The mk2's and some of the 1's have it on the left side. Left and right side mags are not interchangable. The frame's are different.