The 826632-4: The 0.110" (2.79mm) insulation height leaves clearance for passives under the header body on the top layer.
Gold on the mating face (3.90 µinch / 0.099 µm) over brass square pins — the gold layer prevents oxide buildup on the contact interface during storage and repeated mate/unmate cycles. Tin on the post (118.1 µinch / 3.00 µm) is standard for solder-joint reliability in through-hole wave-solder processes. For a signal-level interconnect (0.5–2 A per circuit), the margin is generous.