Do the original AD&D Monster Manual, Monster Manual II, and
Fiend Folio offer anything in terms of raw mechanical content that isn't also present in the AD&D 2e Monster Manual (black cover, revised printing)? That is, does the AD&D 2e book cover a similar amount of ground as the original three books, mechanically speaking? Also, AFAIK , monster manuals from both editions of the game are 99% ...