Does the Astro in Hunts book appear to have the early brown Micarta in your opinion? The pictured knife looks very much like the one on the left that I own, but it definitely has the later mid-60's brown Micarta.I have noticed much variation in the distance between bolt holes in these Astros. perhaps due to the fact that they were hand done. Don't know if they had a standardized jig that they used for that, but there are definitely differences.
This brown Micarta below has a different spacing for the bolts. The front hole seems to be relatively the same, but the back one is closer to the thong hole on the 2 pictured together. I have noticed that on the early training Astros too.
It seems these early training Astros had larger cavities for the astronauts. Mine is not as large, but larger than the standard of later years. This would explain the greater distance between bolts.