Without seeing the pattern, it’s kind of hard to tell. But here’s a link to Debbie Bliss pattern errata. I don’t see the book you mention, but the pattern may be a reprint. It’s worth a look: http://www.debbieblissonline.com/PatternRevision.asp
Good luck!
A drop shoulder won’t have armhole shaping, it’s just straight up. Look later on to see if it says to sew the sleeves X inches down on both sides of the shoulder seam - that’s a drop sleeve.