Tim, that was some in-depth research you did. Dionne doesn't say where her grandmother lived, but if it was Maryland, I think you are onto something.
I didn't find anything on Google about these daylilies, but the AHS hybridizer's list shows that it is William Kimble from Baltimore, Maryland and that he died in 1988. The list shows Diane Summers as the co-registrant, also from Baltimore. Would this be the right state, Dionne? The other Summers listed is Alex J. Summers from West Roslyn, New York.
You might want to try contacting some of the clubs in the region, which covers Delaware, District of Columbia, Maryland, New Jersey, Pennsylvania, Virginia and West Virginia.
http://ahsregion3.org/Page/LOC...
Good luck in your search, Dionne.