The 6020 12-string was a brief and wholly unsuccessful foray into acoustic 12-string territory Gretsch made in the late 1960s and early 70s.
According to Dan Duffy, Gretsch quality control guru, sales were always poor, and the few that did sell caused a lot of headaches at the factory.
It took a lot to get these guitars in shape before they were sent out. If the company made 100 of these thats a lot. The only time they sold was when a record came out using the 12 string guitar.
It debuted around 1969 was discontinued around 1973. In the 1 April 1970 price list, the 6020 is listed under the "Guitars (not illustrated or listed in catalog #33)" at $295.00 retail.
0 examples are in the Gretsch-GEAR database.