PS - use the Vintage Drum Guide and check out the Rogers catalogs and you'll see the various mounting arrangements over the years. By the way, the black strata is actually a Starlighter layout. It doesn't have the knobby for a splash. My mistake.

And a bit further on this:

Rogers' engineer, Joe Thompson, seemed to be trying to make improvements in drum hardware for the sake of the drummer when he developed the Swivomatic and knobby mounts. Comparing what he did to what existed at the time, we can conclude that he was successful overall.

One aspect of that was an idea that the more he could mount to the drums themselves, the less hardware a drummer would have to lug around. So early configurations show snare drums mounted to that rear hard left mount (like you have) and toms mounted on the front of the bass immediately forward of the snare mount. Keeping them on the hard left side allowed enough room to mount a sizeable ride on the bass too without interference. He also set up knobbys on the floor tom so that the only hardware you needed with a stand was the hi-hat.

As time went on, drummers seemed mostly to abandon the mounting of the snare to the bass. At that juncture, you find the tom in the rear mount and a splash in the front mount, which is essentially the Cozy Cole layout.

Again, check out the older catalogs available on the Vintage Drum Guide link and you will see all those optional layouts.