They look like the ones that were on my 67 Grand Prix. If I remember correctly there is a spring clip on the inside (where the arm extends). Just use a screwdriver on it and lift up. The other small arm has a clip and should be easy to figure out.
Restoring a 1968 400 4spd, numbers matching Firebird Coupe, Verdoro Green. Larry My old 68. Wish I had her back.
