No.
The maps are dungeon maps, and the Letters depict the Monster. For instance in this map:
http://www.wizards.com/dnd/images/DungeonMap_166/2.jpg
If I were writing the adventure I would say the C was a Carrion Crawler, the S were Shambling Mounds, and the G was a Gelatinous Cube. I don;t know if that is what they actually are, but you get the idea.

