Hi Ron & RML - the plastic dummy grip thingie for the PZ1/PZ1P is a genuine Pentax part.
It is also available with a leather handloop thingie that was part of the neckstrap. So you can just slip your hand into the handloop and carry the camera safely around that way. Actually that's probably the most useful features of this grip since all it is is a piece of molded plastic.
My Z1P dummy grip thingie has with this handloop thingie. But I seldom use my Z1P because I love using my MZ-S.
Wow, that's news to me. I thought I owned anything Pentax that existed for the PZ1p. Had 3 of them in the '90's...still have two...(I too prefer the MZ-S)
Since I'm a "no strap" tripod only kind of guy, perhaps I rejected the hand grip due to it's apparent strappy thing? Just don't recall...never did get my entire short term memory back from the '70's and '80's...
I'd love an MZ-S, myself, but the Z1-p has interesting qualities, the grippy thing is a minor factor, though.
Even if it does nothing, it could be useful to me, to steady any longer lenses. Batteries at least make good ballast, but when I want my Canon A-series cameras to be lighter to carry, I often just dump the batteries and leave the little winders on to keep the handling.