You did really well with those two.
The strawberry Delrin 612407 toothpick was made by Robeson in Perry. New York, between about 1959 and 1965. They went from genuine strawberry bone to the Delrin about 1959, some say 1960. They went out of business and closed up shop in 1965.
Robeson introduced the "Frozen Heat" cold quenching process sometime after Emerson Case came to run the company. He was hired shortly after 1940, but I think the process was introduced after he became president in 1948.
Mr. Levine has documentation on that, as He has written about it previously in his KnifeWorld column.
Robeson produced several patterns, indeed sets, of kitchen knives with the "Frozen Heat" process, but the only folding knives I'm aware of that were treated with it were the post WWII 872 swing guard folding hunters. They were made with stag, bone and yellow composition.
Your stag folder, however, was produced by Queen, most likely sometime in the 1990's. Actually, it should be dated with either a two digit or four digit year date on one of the blades.
I don't think Robeson ever produced a stag handled serpentine knife. And I suspect Queen did not actually follow the original Frozen Heat technique when they made that knife. They simply applied an old Robeson blade etch.
Robeson simply etched their blades, "FROZEN HEAT".
Queen produced Robeson reproduction MasterCraft knives don't actually have a bronze bearing on the ends of the blade tangs and some of their so called PocketEze knives don't have flush to the frame blade backs.
Regardless, the two knives you have are worth significantly more than you paid.
