[Wingnut]

I don't think that's a misprint (unless you mis-printed the quote, which is possible considering your post says "giving you the and gut-shot"). "Gut-shot" refers to any 4-out straight draw (i.e., not just your typical "inside" straight draw, but also A234 and AKQJ, which only make a straight one way).

In your example, yes, having Ac4c would be a better semi-bluff (now having the gutshot and the flush draw), but you can still semi-bluff raise with only the gutshot.