I am under the strong impression this one is 5160. Made as early 1991-92 era. It resembles the steel etch of another 5160 N2 quenched Fowler blade. Some tiny specks of carbon in each of these as they came out of the etching process i think, and they took the etch very similar. Unused condition. Super comfortable grip, reminds me a lot of Ed's old personal user.