Blackjack/Ek No. 5 Variation Question

[Hazardous]

I recently acquired a new Ek No. 5 bowie without the box that is different than any variation I have seen. It is a black paracord wrapped model with a black nylon web sheath. The sheath has a green label on the back that states " Handmade in U.S.A. Ek Commando Knife Co. Effingham, Illinois" I assume the Effingham marking places this in the Blackjack Knives catagory of Ek history. The unusual thing is that the entire knife has a semi-matte black paint-like coating. It looks like the coating was applied before final sharpening, as only the edge of the knife shows bare metal. There are no markings on the knife at all. I like the idea of the coating because this unit is going to be a permanent part of my bug out bag. It should never rust! Any ideas on this variation?