DUAL top of quarter rear antenna's

I am seeking a set of Dual top of the Quarter mount antenna's that would fit my 1957 Fairlane 2 door hardtop. They have special gaskets that are offset (larger on one side than the other to keep the antennas straight up). These were aftermarket and I have seen several sets of them so I know they exist. One of them , maybe both of them, are dummies, I am not sure. They were advertised in the SKYLINER magazine several years ago. Can anyone help me find these? I would be in your debt. :) Thanks,