Is guy unisex?

We usually use the phrase “let’s go guys” while takling to a group of friends, irrespective of their gender.
However, when we say “guys night out” or “today the guys are making dinner”, it’s always referring to men only.
Is “guy” then an inclusionary noun or is it simply sexist??

Re: Is guy unisex?

1.Informal. a man or boy; fellow: *He’s a nice guy. *2.Usually, guys. Informal. persons of either sex; people: *Could one of you guys help me with this? *

http://dictionary.reference.com/browse/guy