Only NOS, and keep an eye on the condition, they would be a couple years old at least.
Is there a reason you want the old ones? The new KO2 is superior design, frankly.
Don't like the aggressive sidewall. At all. Just me, lot of people like them.
I like to run the General Grabber AT2. It is a copy of the BFG all terrain KO2. We have it on 3 different off roaders, they are a long lasting winter rated tire.