Wellllll.....as always, we have to remember that the pattern engineering changes were not like flipping a switch. Frequently, there would be a few thousand finished knives held in reserve for warranty replacement, and every year, some dealers, for whatever reasons, would return some unsold inventory. Schrade would 'recycle' the unsold knives by cleaning them, sometimes sending them back for crocus finish and edge touchup, and then repackaging them for shipment with current production. If the time difference between the production of the four pin knife and the gray box (circa 1985/6) were close, it might not actually be the wrong box, just mixed ECO knives during the changeover. Now, a four pin with serial in a blue stripe or blue/gray box would be pretty suspect.