As said above, with wear the lock bar will move across the tang. But that doesn't mean your knife's lockup is currently safe.
One school of thought is that it is best for the lock bar to be as far to the left as possible while still maintaining a good lockup. This is because as the lockbar and tang wear, the lockbar will move across the tang and eventually to the other side of the handle. Once there is nowhere for it to move any further, any additional wear will result in blade play. Having the lockbar start as far to the left as possible means the longest possible life for the knife.
However, by most accounts, it takes a very long time for this to occur. Realistically, you'll probably die before tang/lock wear becomes a problem. Wear can be a problem for junker knives, but I haven't heard of anyone having to retire a quality knife because the liner or frame lock moved to far over and then caused unacceptable blade play. The lockbar will move, and it may even eventually move all the way across. But I doubt it will be a problem in the forseable future.
The other school believes that having the most contact between the lockbar and tang is the best. This means more friction between the two, and less chance of slipping. A popular knife that follows this school is the Sebenza. The lockbar and tang have something like 85-95% contact. The resulting lockup is very solid and just looks very confident. And Sebenza's have been around for 10 years and there are no reports (that I know of) of tang/lockbar wear being a problem, or even noticable at all.
Enoguh of my blah blahing.
The point is that I think you should do a spine-wack test. I normally hesitant to suggest a spine-wack because I am hesitant to do them myself. I fear being cut, and I fear causing needless damage or wear to my knife that would not have been caused in normal use. I feel a spine-wack puts far more stress on the knife than I ever will. A light spine-wack can at least tell you if the lock is working at all, though.
I think you should wrap a towel around your hand (to protect you) and do a fairly hard spine-wack against wood or something not so hard that it might damage the blade. If it passes, then you should feel safe with the lock even if its appearence doesn't inspire confidence. If it fails, then you should probably send the knife to Kershaw. They have great customer service.
I think you might be underestimating how little contact between the tang and lockbar is actually needed for a strong lock. But we may be underestimating how little contact there is on your knife. The only way to know is to test it. And I think your situation is such that a test is warrented.