It should fit the 103, but is not the same as the current issue 74M/100 series rear sight.
The Tantal/Ekie AK74 guide shows the difference:
Rear Sights
Type AKM - 1978 or so
Type B 1978 or so until at least 1986
Type B sometime after 1986 to current
Type A is a carry over AKM part. Type B had a longer ?nose?, Type C is current type with half ?tick? marks. Left type A, middle type B, right type C.
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