I am not sure that I got properly your questions
You can check the memory to confirm if the program was Flashed properly on the device, but if you want to check if the device was properly soldered on the PCBA you need to perform a functional test.
Normally the customer uses an ICT to check if the device is soldered properly, no solder short open pins, also on the ICT you can use the BSDL file to check the pins, depending if you have access to all the pin you can check if they have contact to the pcb.
After the ICT test normally, the customer performs a functional test, depending on your application and the time that you want to test the product is the coverage that you can have for the MCU features.
Other customers add some validation tests like thermal cycles in order to release the production line. Or cross-section on the device (K22) in order to check the proper solder of the BGA balls
You can add a final test (normally a random test, no 100% test) where you test the product like the final uses and if everything is correct you can release the batch of production
I hope this will help you