Well, for 2u they are the same, but supposedly 6.25u plate mount stabs have a straight wire and PCB mount have a kink in the middle that interferes when you use a plate.
That said, Cherry PCB mount stabs for 7u are straight.
I guess there is variance!
I've been trying to put my 6.25U spacebar stabiliser into my face-u, and I encountered problems with the plate too. It seems to fit in there now, though...
I ordered some PCB- and plate-mounted stabs from QWERkeys a while ago and they both came with bent 6.25u wires, not sure if that is how it's supposed to be. In the end I bent my own straight wire to use in my FaceU.
1.5mm "piano wire", essentially spring steel wire.
The straight one I sent you is just that.
I get it looped and its a bit of chore to get it straight, but you could get 1.5mm pushrod wire that the RC guys use. It is just straight spring steel wire. Make sure to get it long enough, they usually have a kink on one end!
I decided to go on welding rods. Because of the insane cheap price, availability and straight from beginning.
Fortunate I had a plier that the part of the head that you hold with is almost exactly the length of the "legs" on stabs.
But do you know how long all stabilizers are when straightend? Would be good to know.