Yes when you are making homemade sauce you can put the meat into the sauce raw and then cook it with the sauce.
There's no need to precook the raw meat first before adding it to the sauce.
As you cook the sauce the meat will also cook in the sauce as well.
When I cook my sauce with the raw meat I cook the sauce for around 6 hours which is usually enough time for the raw meat to fully cook in the sauce.
Sometimes depending on the meat in the sauce it may be fully cooked within 4 hours but some meats in sauces take 6 hours.