I say get both opinions if you can. I've consulted with several docs and each has a different opinion about treatment options and follow-up care. TOS is so far from being cut and dried that it is important to get the right advice/treatment plan for your specific case. If it means seeing multiple docs, then it's worth it.

About the wrong limb thing, WOW! I'd hold off on saying anything about it until you are 100% sure you are going to have the surgery with him. No sense bringing up an awkward subject that might derail the appointment when you may not even go with him as a surgeon. If you do end up having surgery with him, you can ask the team who gets you ready for surgery to mark your correct arm.