Quadrature assumes two signals 90 degrees out of phase, and these are more like two 50% duty cycle clocking signals with a very slight delay between them. You could still derive direction information by noting which clock transition arrives first.
With these gear motors, it's highly unlikely you'll not know what direction they are turning unless they are being forcibly back-driven. In these instances, quadrature adds value because 1) it increase the effective resolution of the disc by either 2X or 4X (depending on how you count the transitions) and 2) it allows you to better discern between valid and invalid transitions. If the disc is sitting right at a transition the output of the optical vane could stutter and send long streams of pulses, even though the bot is not moving. You know the transitions are not valid if the opposite channel is also not changing.
The disc with 36 "fins" will also not quite produce equal mark/space signals, as the distance between the fins is larger than the width of the fins. This is probably okay as you can compensate in software (or the software just doesn't care). It *could* be a problem in hardware quad decoders, like the ones US Digital sells. Their chips are pretty tolerant of timing delays, and they include internal pulse stretchers. These discs are probably okay, but if the mark/space ratio is ever too asymmetrical, the chips no longer perceive the A/B channels as quadrature, and the output is erroneous. Since these discs are being done on a laser there's always the opportunity to fine-tune their geometry, should it be the case that hardware decoders can't handle them. But again, the spacing of the 36-fin wheel is probably close enough to do the job.