This Gretsch looks like a 6120, but has Hi-Lo Tron pickups (like the Anniversary model).  The serial number is hard to read - 680xx or 670xx (see photo). With the exception of  deterioration of the white binding on both the top and back edges of the butt end (see photo), the guitar is in good condition.  It was gigged occasionally in a local jazz band and has great warm jazz sounds using the neck pickup with my Vox AC-30.  (For blues, I used the two-pickups setting.)  Strung with 11s, it plays like butter. 
Appraised by Gruhn in November 2015 for $3,500 - $3,750.  According to George Gruhn, "The body conforms to the specifications of a style 6120 with orange finish, open F holes, laminated maple construction, and white binding on the back, top, and F holes, but it features single coil Hi-Lo Tron pickups.  It has a Bigsby tailpiece as is typical of a 6120, but the pickguard appears to be of a later vintage with a Gretsch logo with no Chet Atkins logo.  The volume knobs are the style used during the late 1960s.  The neck is similar to a style 6120 constructed of maple with a dark center lamination and the fingerboard is of the same style as a 6120, but the peghead is unbound featuring a Gretsch logo with no other inlay. (Appraisal will be included when shipped.  Buyer pays shipping, estimated at $80.)