This is one of the few Sony models of the period that doesn't have the model number molded into the circular mark at the lower left. The back cover of the TR-77 also includes the words "UNBREAKABLE CASE" on the lower right, below the vents. I'm sorry this lettering doesn't show well in the photo; I plan to update it later. And by the way, I have seen a broken TR-77 cabinet and broken back cover before.