Its possible without the Supermarine factory being bombed that could have happened, but thats speculation. I think a lot of Mk III stuff was destroyed.Dowding was probably in the right place to order two things:
- use the Spitfire III as day-fighter only
- revert to the 'normal' with tips as on other Spitfires
Unfortunately, Spitfire III never attained the production and service status.