So according to the forum encyclopedia, the 1st engine with a starter was 2815891 in Dec '18. Was that also the 1st engine with the provision for a starter? I seem to remember a car with a slightly earlier # with a starter. How could a starter be added to a non-starter car? Or, was the casting changed to accept the starter a bit earlier than when they started installing starters?
The transmission cover was changed to add a starter mount. The flywheel was machined to accept the starter ring gear. Those same changes can be made easily to any 1911 - 18 Model T engine. The engine has to be out of the car to change the flywheel of course.
The engine block was modified at the timer end to mount the generator. That means you can put a starter on an earlier block, as Royce mentions, just not a Model T generator.