This is one of 3 double sets Buck used to make. Yours is called the Sportsman. The early factory production sets had sheaths with keeper straps and then later, the sets came with flap-over type sheaths. The Twinset was model 104 and offered the 103 and 102 models. The 117 set featured the 103 and 116 models. I suspect that your knives are the 3 liner vintage since you knew the model numbers and I would value that set as being worth $100, maybe a bit more. The two liner and especially the 1 liner sets are worth substantially more, especially barrel-nut sets with keeper strap type sheaths.
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"He is no fool who gives what he cannot keep to gain that which he cannot lose".