If I recall correctly, the base GT3 mod only comes with a single "Test Car" for each car model. It’s seemingly expected that you’ll fill out a field of cars to race against with a skin pack. It would therefore be up to a skin pack’s author to provide talent files.
I’ve pretty much settled into ThatAudiFan’s Blancpain Endurance Series skin pack which does not come with talent files. Beyond that, I can’t really offer which skin packs do or do not include corresponding talent files for their vehicles.