Check the "Sold" listings on HIfiShark.com. Click on the "Sold/Expired" tab and then on the "Site" label at the top of the listings to narrow down the results to specific geographic areas.
https://www.hifishark.com/search?q=Rockford+Fosgate+t212d4
https://www.hifishark.com/search?q=Rockford+Fosgate+t212d4