Nope! I'm sure I read a few MZBs in my teens, but the only thing of hers that I remember reading is a later Avalon book that was an origins thing in which it was made clear that Guenevere incarnations would always be weak and whiny and Morgan incarnations would be pure and virtuous and awesome, with an ever so subtle "Of course! Which is pagan, and which is Christian, after all?" undertone.