Tom, I have an answer for this one. I bought this while I was passing through a small town more than twenty years ago, the kind that if you blink you would miss it. Seen a store, parked and went in, looked like an old hardware store but they sold groceries and a little bit of everything. Looked for a knife display didn't see any and was walking out, the middle aged clerk asked me what I was looking for. I said old pocket knives, he reached under the counter and in an old cigar box were about a half dozen of these.
I took one out and was disappointed it was Delrin
asked how much and IIRC it was about $20, I bought just the one you see here 
should have bought them all! 
