I have a 444 with a 1997 tang stamp. Bought it used, just use it as a utility knife. I've peened the pivot pin to tighten up blade play, but there is significant lock rock. Just for the heck of it, I decided to do some medium intensity spine whacks and overstrike test on my table. Surprised the heck out of me. I fully expected the lock to fail, but it didn't.
Never underestimate a Buck.
Never underestimate a Buck.