Since there really isn't anything to do about it, I'd shrug and forgive myself and move on. I am taking a course at Oxford and posted that the Norman Conquest was in 1266 instead of 1066! My little brain had 1266 on it at the time. Mistakes happen and often don't even get noticed. It is just finding a book, they'll look up the book title later themselves, maybe assume it was not "in"/on the shelves since they could not find it under your name, etc., if they really "need" the book they'll find/figure out what has happened and maybe even assume they heard the name wrong themselves but probably will just realize you had that other author on your brain. Remember, too, they are dealing with this one-at-a-time, they don't know you told 42,000 people the wrong author just them so it does not look like it does to you.