30-908 - 6- Position Adjustment Bracket (Natural Nylon) 10 5/8" L x 5/8" W
This part may be screwed or riveted to the frame. (Attachments not included) It fits on a round tube. It may not be the same as the ones you want to replace, but you should be able to adapt it to work for you. It is attached with aluminum rivets or stainless self tapping screws.
