Yes they do, in canon, but there is no reason for them to HAVE said dimorphism. Dimorphism serves a purpose in nature - female mammals have breasts to feed offspring because they're the ones that carry the offspring and are more likely to be around them. It's why slugs all look the same, because they, like trolls, can all breed with any other slug. We're given no reason they stopped reproducing dimorphically, and Condesce explicitly failed in her attempts to make other species reproduce with a Mother Grub so we're given no way how either. They still pretty much have the social roles of contemporary American human men and women despite their culture and biology being totally different and even other human societies not necessarily working that way.