The "grittiness" comes from the lock riding on the blade as it pivots. The lock is spring-loaded and rides on the round part of the blade that leads to the locking notch. If that area isn't smooth, you will feel the roughness. Lubing and cycling the blade will smooth it out.
The other problem with some early new models is the slot in the scale for the lock release bar is cut a little short. Consequently, the lock bears against the scale when it is disengaged and won't let the blade swing freely. Again, lubing and cycling will cause everything to wear in and smooth out.
I got several in stock a few months ago and they ran the spectrum from pretty smooth (stonewashed) to a bit rough, especially on the black ones.
I only had to take one apart, though, and that was to smooth out the round bearing area of the blade for a customer. He was happy with the results and it only took me a little while to do the job.
It doesn't affect the lockup in any way and the knife will smooth out with use. It will take several hundred cycles, though, to get it really smooth, as most of you have found out.
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Dennis Wright
Wright Knife & Sporting Goods
(Buy a knife...confuse a liberal)
La Mesa, CA
wrightknife@ixpres.com