I know I'm a bit late to the thread but I figured I'd chime in and share my experience with their customer service for anyone who may be interested. I picked up a used old lock geometry SMF from a guy who said that he was issued it while he was in the military, but it lacked an NSN number. I didn't care about the number I just wanted a user SMF. After months of daily use the the thumb stud came loose and fell out so I followed their instructions and sent the knife in. I never got confirmation that they received it other than the tracking information showing it had been delivered. A few weeks later the knife showed up on my doorstep and not only had they fixed the blade stop they also converted it to the new lock geometry and added an NSN number to the blade. I hadn't mentioned anything about the lock geometry or NSN number and I thought it was a really nice touch on their part. I wasn't sure if they had put a new blade on the knife or if they had added the number and then refinished the blade so I sent them an email to thank them but also inquire more about the blade and I never heard back. I should add that after a few more months of daily use the knife ended up with slight lock rock.