no, they don't
but I believe its sufficient, 'cause if you see the 3rd photo, the m/b isn't bending at all.

I picked a strong one and carefully used the appropriate spacers,
and a less strong, so that it could bend slightly over the other, and tighten the whole structure.

With the stock push pins, my motherboard used to bend (slightly).
I believe Scythe should have made an Infinity rev. B with a backplate.
At my first mount with the stock pins, I wasn't even sure if I had it right.
Too much pressure had to be applied.
This mod rulez