removing a few bits of a stencil to put in the bottom of a cab is a far cry from a whole cab The amount of time you spend futzing with trying to reuse something like that is just not worth it even if you consider your time worth minimum wage.
I wish a truly reusable stencil was cost effective, but it's far from it really. By the time you pay to cnc metal or wood as opposed to plotter cutting vinyl you're at a cost greater than 2 sets of stencils to begin with, so unless you're one of that less than 2% of people that do more than one restoration of a particular cab the value just isn't there in a reusable version. However, i'm sure if you really do need to do 3 or more of a single cab it's worth it to ask one of the stencil makers to get a set laser cut from metal for you.