When the original Emerson folding knives were made for use with the U.S. special forces, Mr Emerson designed the knives to be able to stand up to the wear and tear of an amphibious environment. The original knives had both liners made of titanium for this reason as titanuim will not rust. It's also the reason he uses nylatron washers, grease, G10, and stainless steel blades. As Mr Emersons designs evolved he decided to change things here and there, one of which was making the non-locking liner stainless steel but retaining the titanium lock side. As dr_fosg8 said, if the knife functions properly and the lockbar isn't touching the opposite liner you should be fine. I have a few Emersons with "late" lockup and I have had no issue with any of them failing on me.
