After blowing up the picture you posted of the tractor with the 44six on the hood and taking a closer look, I don't believe this is the tractor you boys had your picture taken on years ago.
If you look closely it appears you can see the long stem pole on the seat that goes to just above the transmition cover wich is used on the later tractors.
The picture you posted of the young boys clearly shows the old style spring used on the 101s just like the picture I posted. Could it possibly be the tractor your looking for is here? Did your dad have more than one Massey or was the picture taken on a neighbors tractor? Just a thought?