What this 3-position header is built for
The 5-104361-2: The 4-wall shroud and latch holder mean it mates positively with AMPMODU MTE crimp receptacles — the latch clicks home and the keying slot keeps the orientation right, so you don't get a reversed wire harness on the line.
Board lock and keying slot — what they do for the build
Without it, a yanked wire harness can lift the solder joints. The keying slot in the shroud aligns with a matching rib on the receptacle housing — it prevents plugging a 3-position header into a 4-position receptacle, or mixing up circuits in a multi-connector panel. That matters in medical and telecom gear where a mis-mate means a board respin.
The 3-position 5-104361-2 uses gold on the mating face, which buys you more mating cycles (field-service or test applications) over the tin sibling's cost-optimised build. For 3 circuits with repeated mate/unmate duty, the gold plating on 5-104361-2 is the right call.