The 747 was initially certified in the US without any stall warning or protection at all. Boeing considered it's stall performance so good, they didn't think it needed any artifial warnings and the FAA agreed. It was the UK CAA under the direction of DP Davies (author of Handling the Big Jets) who insisted on some form of warning for UK certification, so the stick shaker was fitted. This is why it is a motor with an eccentric weight, jubille clipped to the contol column and looks like it was designed by Heath Robinson.
It was subsequently fitted to all 747s.