I doubt it. There are so many vehicles, especially historically, from Toyota Tacomas, Jeep Wranglers, Honda Civics, to yes, Porsche 911s that are available with both AT and MT. Considering the number of vehicles insured in the US, and the fact that you can do paired comparisons like this, if there is a meaningful difference, insurers would see it.

edit: link from State Farm, a large US insurer. https://www.statefarm.com/simple-insights/auto-and-vehicles/....

Studies haven't really shown which transmission type is safer. Automatic and CVT transmissions do allow you to keep both hands on the wheel at all times, while manual transmissions may require more attentive driving. Your driving habits will play a large role in your safety. Safety features available for both automatic and manual vehicles can make a difference, too.

I’m still skeptical there’s enough data to distinguish from the obvious selection effects. The difference in safety between manual and automatic 911s probably tells you essentially nothing about whether a random driver would be safer driving a random automatic or a random manual.

It is hard to distinguish indeed, since there is no noticeable difference.

Jokes aside, as a data scientist of a long career, I don’t share your skepticism. It would be a hilariously easy task to extract this information from the data with the variables involved and the records insurance companies are able to keep.