I agree that the "AC" looks awfully funny, especially next to the "AY" copy in the catalog. However, Very Fine Books had copy "AF" up for sale a while ago
https://www.veryfinebooks.com/Stephe...st_p/sk879.htm
and it also had a much different looking "A" than the one in the catalog. So it appears as though there were two letterers? The Heartwood Books one doesn't have a very clear picture, though, which doesn't help...