I'd guess this depends on region/demographic, but at least in my circles on the west coast, "guys" is gendered when it's used to describe or identify people in the third person, but it's gender-neutral when used to address a group of people in the second person.

So "the guys" or "how many guys" always refers to men, but "you guys" carries no implication of gender at all. I often hear people address groups consisting entirely of women as "guys", and nobody bats an eye.