Did they drain and refill the old coolant or put new antifreeze in? If they put in new antifreeze, it will likely be itemized on the bill.
Replacing coolant regularly is REAL important on GM vehicles that use Dex-Cool (Dex-Mud), but Chrysler doesn't use that junk. The reason for replacing coolant is to get out the acids that naturally form that could eat away metal parts, and to replenish the additives that wear out. Those are water pump lubricant and corrosion preventers.
Two years is the recommended interval to replace coolant but I wouldn't lose sleep over it. There won't be any catastrophic failure if you're a year late.