issues with cts blend pot

I just got a 500k cts blend pot the other day. With the washers and nuts properly installed, the damn pot doesn't evenly mount to my jazz bass' cover. It 'leans' to one side on account of a protruding metal piece.

anybody else have this problem?

anybody have a solution? - I was thinking of gluing some foam rubber to the gimp side so that it's leveled with the other side.