ASFKAP,
Didn't know 73's had stick pushers, I thought it was just the superstall suseptable a/c, i.e. T-tail types like the 727, which I know for sure had pushers installed. (but as previously stated only on UK reg'd a/c) In fact US reg'd a/c didn't require 2 stick shakers either, and I think they were only fitted to homogenise the production line
The 757/767 do not have pushers, only shakers, but they also have a additional recovery system in that if slats are at the intermediate position they will go to fully extended in the event of a stall warning.
The second system which detent is talking about is a speed trim system (more akin to mach trim than stall warning) and as he has stated prevents over rotation of the a/c due to the rotational torque produced by thousands of tons of thrust from engines slung under the wing.