Harry,
You should check to see if there is any side to side or up and down play in the blade. If the lock-up is solid, then you should not have any problems. These liner locks will wear in in due time with repeated opening and closing.
My AR is absolutely perfect in lock up, with no bladeplay. The lock was very similar to yours in its position when I first got it, but has worn in and is fine. Again, just make sure there is no play in the blade when locked open.
Regarding the grittiness. The AR and GB (although some may argue this point) is not a "gentleman's knife." (Okay, most Strider people are gentlemen.) Therefore, most of the folders I have handled were a bit tight and gritty, but you can use some lubrication and is should help it. You can also loosen the pivot screw, but you have to be careful not to let that effect the lock up, so it's probably not a good idea. I am fortunate because my AR is "unusually" smooth. Hey Mick and Duane...what's up with that? This ain't no sissy knife!