older Bucklite 426 with "black" blade

[chickentrax]

Just got one of these in, and as you may imagine, the blade is a bit scuffed around the pivot area.

Does anyone know exactly what the "black" is??? Is it Teflon, or black primer, or some kind of anodizing???

I haven't decided whether to strip the "black" off, or try to refinish it...Knowing what it is would help me decide...