Having trouble understanding how the lower A/C duct is used on a 68' with floor console. Came across a parts site that list 2 versions.

Type 1: http://thepartguy.com/images/PartsForSal...erFloorDuct.jpg

Type 2: http://thepartguy.com/images/PartsForSal...erFloorDuct.jpg

When I bought the car the seller included an uninstalled lower duct that matches the "Type 2" photo, the other LH and RH lower ducts were installed along with the LH/RH dash vents. I have looked in the shop manual and see where the lower duct attaches but am confused on the 2 styles and the overall look and function. Anyone have any photos of one installed or can help explain?