Here is a George Butler knife without a "Key" stamp or a "Art" stamp on the pile side.
I don't know if that helps date this knife or not. I don't even know the name of the pattern.
This is the first one of its kind that I own. I paid $3 for this knife at a flea market.
It has some sort of composite/plastic covers.
Deal of the day. 3 1/4".