The above is true and Ruger will not even re-blue them. But its not a carbine "I" would take to a Carbine Course and run a couple thousand rounds through her. I have one that I paid $500 for in overall good to slightly less than good condition with a seriously dinged up stock and wooden handguard, but it had one of the early 20rd factory magazine .
In my case, I'm still trying to find somebody to make an exact copy of the original stock and a matching handguard in walnut. She is basically a safe queen since its mainly for sentimental reasons... I was with my father as a young teenager when he bought one back in 1976 and it was one of the guns that got me into military/para-military firearms.
If those two 30rd magazines are true Ruger factory pre-ban versions, "I" would say that $550-$600 is fair to good... If they're aftermarket mags, $500 would be my max and I try to hold out for $425-$450.