I don't know what the difference is between the 2 and 3. The lace lock system is the hook above the bottom lace eyelets that is on the side. It 'pinches' the laces and holds it in place. To undo the laces on mine, I have to give a decent yank on the laces.
My view of those boots is they are a good boot for low/mid (carrying) weights. They are light and comfortable enough to wear all day, and supportive enough (for me) for a 30-40 lb pack, but I feel a little lacking when packing out an animal (>60lbs) in steep terrain. They worked well, but not as well as stiffer, heavier boots for backpacking. They wear fast, are prone to leaking (from what others have said), but in saying that, I'm going to be getting another pair for this upcoming season. I feel like they're a good blend of comfort/support with low to moderate weights for moving quietly while (archery) hunting.