Hi Can-down,
There is no difference between the Sobol and the 7-2-KO as far as the barrel, action and sights. I'm not sure about the trigger though. Initally I wanted to buy the Sobol but after holding the Biathlon which felt better, the 5 mags it came with and the lower price, it was logical I went with that one. The front round flange in the trigger assembly is indeed the safety lever that you move up or down with your index finger.