The RDs were made 1977-79 , about 900 total production. Somewhat rare these days.
This example has a genuine honest relic look ( an added cost these days from some manufacturers )
Marked SECOND on the back of the headstock. Back in the ’70’s some Gibson instruments bear this SECOND impression , which nearly always indicated there was a minor cosmetic flaw , usually in the finish. Rarely was I able to spot the flaw. I cannot see it on this example.
Currently sporting a set of flats , the strings can be easily changed to your liking.