WRONG.
The XXXX to mark blems are put on AFTER the blade is initially lasered with the model #. This should be fairly easy to spot since they aren't going to be 100% consistent with each other, and the rest of the lasering.
They still use the single X today, to mark that, for instance, you have a 1670x. This means it could be a 1670, 1670NB, or any other thus variant of the 1670.
It's merely a placeholder for a more detailed description of the knife, if you will. Particularly since that 1670x blade can be used for any 1670 knife, not just a specific color handle, for example.
Feel free to email me a picture, and I can show it to Kershaw on my way to work tonight my username followed by the word INSTAGRAM [at] gmail