Dual-Link DVI means that the data conductors are doubled up in the cable to handle the increased data rates required for display wider than 1920 wide. It has nothing to do with multiple displays.
Dual-Link was originally explained by suggesting you think of two display "panes" side-by-side, but that is not the way it actually works.
A cable or connector that has missing pins in the central pin-grid cannot be Dual-Link. Dual Link MUST have a complete central pin-grid (although Single-Link can have a complete OR incomplete central pin-grid).