We have 2 pieces of evidence that Gaddis refers to in the Astro chapter of his book.
1) Gordon Cooper was in favor of a Scaleless/taped tang. Page 177 Gaddis.
2) Scott Carpenter had a mod 3 Randall hunter, and referred that info to Cooper, who was spearheading the research on the survival knife for the Mercury program. Page 172 Gaddis.