Were any of Hamilton's 16 size watches actually 17 size?

Not exactly.

In 1900 case makers changed case models. This required that the top plate be turned down to fit the new model cases. So there are pre-1900 16-size movements that do not fit post 1900 16-size cases. This statement was made with respect to the 960, and the 962. I do not know if other grades were similarly modified. I also do not know how much the difference was.

Don