I have been looking in the HMG book closely, and models closely associated with this machine like the Junior Grand does not have a lift knob as seen in the book, but this model of course anyway can have it. Still, I find the positioning of it unusual, since it normally is found close to the person opening the lid...Maybe someone also put a self made lifting knob there, which later has fallen off..who knows really.
I have studied the HMG book, and the triple spring spiral drive motor seem to have been in two versions, with a 1 ¼ inch springs and 1 inch springs, but if these motors look different I don't know. After reading more in the book this was a motor that was used on expensive models, like the New Melba and Chippendale. So now I have to find a New Melba as a donor machine...

Again according to the HMG book, the Junior Grand, that is very close to this model in appearance came with two different motors. Double spiral spring for the Oak version, and triple spring for the Mahogany version. It then makes sense that this model in mahogany originally had a triple spring motor, and if it had, the motors still must have had some differences, since the winding handle of the double spring motor now used, did not fit the original hole. There is a photo of the triple spring spiral motor in the HMG book, and if I compare with photos I myself can take of the double spring motor in my machine, it should be possible to measure if there are differences that causes the motors to need two different holes for the winding handle.
I don't know if I am allowed to upload a photo of the triple spring motor found in the HMG book, I will not do unless someone with authority tell me I am allowed to do it. If it was uploaded, it would be easier to compare it with photos of the double spring spiral drive motor in my machine.