I can tell you the bottom listing has a knife that is older than the first one. The Schrade USA three line listing preceded the two line listing, and in some cases, a three line listing may have been right after they changed to Schrade Walden stamps.
Another stamp that was older than the Schrade USA stamps, was a Schrade NY USA listing. It was also a three line stamp, but was not used in all patterns.
The only boxed knife I have in that pattern is one from the early 90's, and it's stamp is two lines.
As far as the 194OT goes, I don't have a clue when it comes to nail nicks, but I have seen many variations within patterns. Those little subtleties, can only dictate age when you have original packaging or sales receipts that you know are valid.
Also, the blue and silver box was the last box before they shut down the Ellenville plant.
Lastly, if I was considering a 194OT, ... well, they are a very nice sturdy pattern, and there are are many fish in the ocean.