All 4 positions are loaded — no option for depopulating a pin. The 0.830" (21.08 mm) mating contact length gives ample reach for stacking with standard receptacles.
Within the BERGSTIK II family, the 4-position 87916-404HLF is the smallest single-row member. The decision between this and the 6- or 8-position siblings (e.g. 87916-406HLF, 87916-408HLF) is purely a circuit-count match — pitch, plating, current rating, and overall contact length are identical across the series. No footprint or stack-height change when moving between position counts.