Maybe when guybrush was throwing rocks at hermans head, he wasnt actually helping herman to retreive his memory, but was only screwing it up more... at least its better than herman actually being HT marley. but why else would herman know about ht marley unless he was him....? Maybe the real HT marley (assuming herman isnt him), landed on monkey island, and the cannibals ate him, so herman just decided to take his identity.
oh well., that doesnt make any sense, even to me. i'll stop rambling for now.
"Gratuitus acts of sensless violence are MY forte!"