I knew a couple of you would really what to know......
Finally got Phil Gibbs, of AGRussell Knives, formerly of Camillus Knives a photo of this 307. He says: "It is a glob of lead!
After the blades are almost finished, the ones that need to be "set" (bent so as to nest with the Spey blade in the closed position in this case) had their tangs dipped in molten lead to anneal them so they could be bent without breaking.
It is unusual that a droplet of lead to stick to the blade like that, but it did happen."
Inquiring minds want to know. Step two is, I bet it gets the ole give it a pry off try.
300Bucks