I tried it (the Schmitt inverter RC debouncer) and it works great. Ended up using 4.7K, 1K and 1µF. And yes, the chip I used (a xxxLS14) is a hex inverter. Much easier than a 555, although I still want to try that too.
hi CZ,
Ref the inverting and non inverting Schmitt de-bouncer circuit.
Consider what the output of an second inverting Schmitt would be if you connected this second inverting Schmitt to the output of the first one.
That is two inverting Schmitt buffers in series,,, it would be exactly the same a single non inverting Schmitt output, this should answer your original post.