I dug around more in my misc, Sunfish parts box and found what you are looking for, see photo. It had a damaged beyond repair block which I cut off.
$10 + USPS postage. Includes the original pan head mounting screws. If you want it, e-mail me your name and mailing address, and I will compute postage and reply with the total. You then mail me a check, I ship the same day and the part and payment cross in the mail: [email protected]