(snip, I wrote)
Yes. My understanding from many years ago, and likely from TTL, is that it is (was) done using two thresholds. As the clock falls (or rises) two things happen at two different points on the clock transition. Since the TTL databook has schematics for many circuits, it might even be possible to see it.
They are pretty good at figuring out strange logic, but yes, I think that would be too much.
-- glen