That's about the same time as Singer 201 was introduced, which I think was their first rotary bobbin model (except for industrial possibly, but I don't know of any). The white rotary is much older though. The White tension mechanism is rather fancy, as well as a very neat motor setup. Any trace of a light ever being fitted on it?
Most older machines are sort of hinged together, some have meshing gears. How does the inners look?