I can't speak to the optics of 532nm lasers in general, as I only own one that is in a focusable host. (pictured above)
All of the modules I've seen are focussed in the module themselves. All of the non-focussing greens I own, seem to use modules that contain the focussing in the modules themselves, as opposed to containing the focussing in the hosts. I *think* when they make focusable hosts, they must use modules with less or different built-in focussing.
I'll post a photo of this module, maybe someone more knowledgable than myself can solve the mystery. Is this maybe just an extra lens at the tip of the module?