Measure the barrel to the front of the breech face. It looks a bit shorter than most rifles. If its a cadet rifle, it may change the value some, unless it wasnt factory original in that configuration.
Should be a date on top of the breech block. It has an inspector date of 84, but the date on the block is the actual model year variation. It may be marked on the lock plate also, but it didnt look like it from the pics. It looks like it has the earleir type rear sight.
Tons of these guns were sold as surplus ages ago, even Sears Roebuck sold them in their catalogs, and surplus dealers often changed them or mixed and matched parts to build guns. If its entirely original, its worth more, as does better condition overall, with good bore. Most that I've seen in decent average shootable shape have been in the $700-$1200 range. If mixed and matched, it may go down a bit. Carbines bring much more, unless they are cut down rifles.
Jackal may have a better handle on current market value.
