Is it possible that on a replacement the left and right control arms could be switched by mistake?

Hello, I'm Danny.

It seems you might have provided incorrect vehicle information. A 2021 Ford Expedition only came with a 3.5L turbo V-6 engine. Can you get back to us with the correct information and we'll go from there. Hope this helps and thanks for using 2CarPros.

Sorry, my engine is not a turbo and it has clearly marked on the air filter (Painted) 4.6 Liter and it is a V8 Thank you for your help. Mine is a 2001 Expedition (my mistake maybe).

Hello again.

To answer your questions no, upper control arms cannot be installed on the wrong sides. They physically would not fit due to design. Yes, the ball joint torque is important to provide structural integrity. Yes, the proper torque is 57-77 lb-ft or 77-103 NM. I've attached the specification picture below. Hope this helps and thanks again for using 2CarPros.

Danny-

Thank you. Most appreciated.

You're welcome!
Thanks again for using 2CarPros and we hope you will use our site again in the future when needed.

Danny-

Thank you.