Sounds like you have the books from the 4th printing. There is only 1 edition of C&C but the various printings have minor differences here and there. E.g. tweaks to the barbarian class, additional spells, switching to color art with the 5th printing, correcting typos, etc. The scope of the changes are nowhere near as pronounced as they were when AD&D moved to its 2nd edition.
The adventure I ran at Nuke Con had character sheets with everything the players needed for the session as it was designed to be both an adventure for players new to C&C and for those experienced with the game. Whenever I run more demos of Zoanthropic Benediction, I'll have the pre-gen character sheets ready for players so no worries about which printing of books you own.