Cinderellas and the FBI

A couple of months ago I attended a local paper show and met a new dealer there with a lot of cinderella stamps. The stamps above are a couple of the cinderellas I found that day. Although he was a very knowledgeable dealer, he couldn't recall their origin. They appear to be selvedge, or a border strip at the edge of a printed sheet. In this case they are engraved with a pattern of nicely script Es, Ds, Gs and what appears to be either a cap I or a T. I am puzzled over these little stamps, but do enjoy them.
      Side story...after a lengthy conversation, I learned this paper dealer was a former undercover FBI plant during the 60s and hung out with members of the Black Panthers and the Weather Underground in order to gather information. He had some amazzzing and very convincing stories to tell about drug running and the life of an undercover agent. He could recall every detail of conversations, parties and events he attended with these political activists. Coincidently he also happened to know my father who was another FBI guy dealing with interstate bank robbers and crimestopping in that era. Our conversation made for a very entertaining afternoon of ephemera and espionage. He is now retired from the FBI and collects cars and blimp ephemera. Go figure. Below are a few more cinderellas, cancelled stamps and poster stamps I picked up from my new dealer friend that same day.