The knife on the left the Capt. mentions, was made well before (late 70's/early 80's) the material he references was available/used. In fact, it was used for a short period when the Westinghouse supply ran out. So, what you have is what Westinghouse Ivorite looks like when relatively fresh and not exposed to the elements - UV light.
The knife in the middle is a seven spacer knife, circa 1972. Again, well before AGM was even a thought by a couple of decades anyway. An extremely rare knife in seven spacer configuration, far more rare than brown micarta.
Lastly, the knife on the right has been exposed to an abundance of UV light and "aged" quite a bit. It to made circa 1974, well before any of the other materials mentioned were even a thought.
In the end what you have is three shades of Westinghouse.