Variants of a mold are catalogued separately, so each one has its own sets and minifigs. Check these too if something you expect is missing here.

• 737c01 Plate Special 2 x 4 with Train Coupler Closed with Hook this part is a sub-part of it
• 737b Plate Special 2 x 4 with Train Coupler, Open for Magnet [Flat] Mold of this part