Not meaning to be awkward here, but it was previously mentioned that the a/c was configured with flap 30 at the time, thus making it likely that it was during the last 1200 feet of the approach. Wouldn't that make a full stall recovery a bit unlikely?
Much more probable (if true at all) that the speed got low for whatever reason and the stick-shaker triggered. This in itself isn't that uncommon - my Company used to operate the B737-300 and I can remember at least three occasions when reports were filed for stick-shaker activation: twice due loss of situational awareness when dispatching with A/T u/s, and once due to the A/T being disconnected when a/c was high on glideslope.
Also, this would not be noticeable to the pax... however, a full stall recovery losing so much height, with 45 degrees NU pitch, at 90 knots with overboosted CFM's... I'd say that the pax would find that mildly uneasing. It's not like they would just get off the plane thinking "well that wasn't weird at all, was it?"... I had a pax phone a newspaper once just to report that we had stopped the a/c on the runway, and he'd never noticed that before (?!)...