Depends what type of map you are going for. If you are going for a battlemap then I'd say a zombie encounter changes the dynamic altogether (at least it would for me personally as a DM); slow moving creatures that you fight in hordes ([Minion] or [Swarm] mobs) so terrain would play a massive factor. They are mindless creatures so creating bottleneck areas on a map would work for a zombie, where they wouldn't work for a vampire/werewolf. Regardless I think if you focus on a battlemap then most of the time the monster you are using could be interchangeable anyway; Mall/Police Station/Ocean Liner/Cemerety/Spaceship ... with Vampires/Werewolves/Ghosts/Swamp Creatures. If zombies are a threat that were known about then suitable anti-zombie defenses could play a major part on a map, battlemap or otherwise.

That said, I'm fine if the higher powers saw this and thought "a monster/halloween theme is a good idea" but didn't focus on zombies