I believe in 1940 and later, the electric start was an option. My '42 B was crank start from the factory but had the hole in the torque tube for the starter and the tapped bosses on the block for the generator. The factory location for the battery box is not off to the side but is as Sheila says...immediately forward of the vertical support for the steering column and centered on the torque tube between the engine and transmission. The crank start toolbox was longer and would not allow space for the battery at that location. When my B was retrofit for electric start, several inches had to be cut off the toolbox to properly install the battery. As Sheila says, some had a foot push rod that actuated a switch at the starter. My retrofit had a manual hand pull rod that accomplished the same thing. As far as I know, there were no push button solenoid start provisions from the factory. That can be retrofitted rather easily though, as I did.
An electric start without a generator does not make a lot of sense to me, and is why I suspect your is not a factory installation. As Tom says, the factory location for the generator was on the front left side of the engine. I suspect your engine block will have the bosses for the mounting bracket. In order to mount a generator you will need two brackets, one for the bottom to support the generator and one for the front top to permit belt adjustment. You would also need a longer drive belt. See attached photo for generator location.