If the car has been without refrigerant for a year wouldn't there be some risk of corrosion and therefore potentially some harm to the expansion valve and other components?

I'm interested in this because I have to replace the condenser and I was taking a similar approach- replace the condenser, receiver/dryer, expansion valve, O-rings and Schrader valve seals, and then recharge with R-12. It appeared practical to replace all the small cost items that can end up creating further costs if not dealt with in one job (excepting the evaporator which, of course, is another job in itself).

Thanks for your comments!