And the answer is: no, it doesn't work simply saving the morphs though the GUI. At least, not that I could find. Sorry. There are other's who've forgotten more than I will ever know about Poser, though, so maybe there is a way to do that.

As for scriptable, pretty sure it is. And I think scripts can be triggered by a library entry. iirc, some of the v4wm's do that, as well as commercially available joint fix injections (for v4). I'm working on a script that will take a bunch of La Femme face chip settings and turn them into a single master. It's tedious in the extreme wiring dozens of parameters through the GUI. It's tedious enough messing working with those parameters to get the expression (pose) in the first place. Need a one button (save facial pose as expression). Soon :)