I believe that's an NMH-91-- a longer barreled version of the MAK-90, and they have that funky lower handguard.
Worth $450? Not to me, but if it's in really good condition it's not a terrible price. That long barrel might be interesting, but for a little more you can get a Russian Vepr, which has a true heavy (RPK style) barrel and RPK bolt lugs-- more heavy duty all around. Otherwise I'd prefer a standard config AK. That being said, I've heard from customers who have NMH-91s and like them.
Wear spots will be at the bolt lock lugs, front block "kick off" cam, cocking tang on the back of the bolt carrier, camming surfaces between the carrier and the bolt, the top of the hammer where the carrier rides over it. I've seen MAK-90s that were completely shot out (I'd be afraid to fire them-- that bad) and as stated, others that were like-new.
Some used AKs I've seen had been "messed with" by previous owners trying to do trigger work and other custom work. Some of that work is OK, but most of it is horrible. Cheap guns are more attractive for the novice as "project" guns, so buyer beware. I guess it's the good work that remains unnoticed.