The link is not working for me so I'm not sure what a cored straight pull mold is. If it's what I think it is, it looks similar to this

but, in the instance of protomold, in aluminum for rapid prototyping. If so, I'm not sure why a 2 part button would be necessary. There are no undercuts that would prohibit a straight pull on the buttons or knobs with a 2 part mold. (Actually there is one on the down button but it can be modified.) If the cutting edges of the molde are placed at the base of the button before the stalk then they should come out of the mold just fine.

Am I misunderstanding what a cored straight pull mold is?