It is definitely Korean on the stock. The pictures made it hard to read what it says (Hyon Dan Tak Na?) and I have not had to read/translate Korean in many years.
These rifles were sent to various units and then the units would take either a paint brush or a can of spray paint and print the info on them (Unit name and location).
I was in Korea from 1985 - 1993 and the only places I saw this type of rifle used was down country at some of the smaller com sites and once in awhile I would see a patrol along the DMZ with them. By my time in country, most units had switched over to the M-16.
Just based on the condition of the stock, with-out the paint, I would not imagine it would be worth much.
Inside Every Bright Idea Is The 50% Probability Of A Disaster Waiting To Happen.