The 3rd knife is an early brown Micarta Solingen stamped on the Ricasso!
It is speculated that it was perhaps from the 2nd or 3rd batch of Astros ordered by NASA. We know that the 1st batch of NASA knives had the RANDALL MADE ORLANDO FLORIDA etched stamp, but could it be that the 3rd batch made in 1962 did not? Also note that it is in a canteen snap hkl sheath, with a vertical Randall stamp.
Whatever the case, it's the only brown Micarta Solingen Ricasso stamped Astro that I have seen. The brown Micarta is of the earliest batch, as used on the Astronauts personal knives.
Gary noted that the Micarta has a spray substance on it.
