FWIW, the eBay grips are most likely modified, and not by the man who carved Kearsarge. He would almost certainly have surrounded the stars with oak leafs, not seen on one of the grips. I find myself wondering if somebody modified a set of Kearsarge grips, by first sanding off a lot of the original dimension. The small amount of background "dotting" within the wood is another clue. Very strange how that just sort of fades away, like no set of Kearsarge any of us ever saw. I doubt he would not have used genuine ivory either. Finally, the design with the star does not appear to function as any sort of finger/hand wrap around the panels. It is not a part of a hand fit, in other words, something he was an expert at.
I have sent this link to his family and they agree the stars are not original to the grips and that their father is not who modified this set of grips..