I thought that these parts would be the same between Mustang and Cougar, Not.
Probably cut from the same rubber hose,? depending upon the diameter of the out bumper bracket tubes. The ribs look the same in a previous picture as my 2-1/2 inch insulators.
1967-68 Cougar outer bumper tubes are 1 inch in diameter. The insulators are from a rubber hose approximately 1/8" thickness, with a 7/8" inside diameter. They are 1-1/2 inches long and per the body assembly manual have a part number of C7WB-17B947-B.
1969-70 Cougar outer bumper tubes are 7/8 inches in diameter. The insulators are from a rubber hose approximately 1/8" thick, with a 13/16" inside diameter. They are 2-1/2 inches long, I found a number in the Mercury MPC, D0WB-17B947-A. There would have been a C9... number too. I have two examples with slightly different side wall thicknesses.