YES, it is the last 6 numbers of the engine number. It's just easier to get it if you have the correct warranty book, instead of going after the stamped number on the block.
I would usually rumage through the glovebox to get the number (to find the owners manual stuff) rather than try for the engine number off the block itself.

Gilly

ps, it COULD also be the last page in the maintenance manual, so check there also.