Filling out the HM/NM books [Duncan]

Can I beat the first four bosses in normal mode, then kill Duncan in hardmode to get it on my HM guide? And then beat all five on NM for my NM guide?

I may be wrong, but I beleive that slavers exile doesnt go to the books since it has mini-dungeons.

http://gw.gamewikis.org/wiki/Master_Dungeon_Guide

Yes you can, that's how I did it. I hero/henchied the other bosses in normal mode, then went back to town and found a pug to do duncan in hm. It added to my hm book, my master of the north title track, and changed the dungeon icon to the gold chest so yes it counts.

Thank you very much banshee.