Was the last fluid change done on schedule? The answer may help us here.
Personally, with time of the essence, I'd lean toward changing it to be safe. I'd hate to go 1,300 miles with questionable fluid. Also, check your owner's manual for the recommended procedure. If it calls for just exchanging fluid without a flushing procedure, make sure they follow that. Also, make sure you double-check the fluid level before you leave.
For what it's worth, in the future, I'd recommend not having service done so close to a major trip. It's good to be able to drive around town for a week in case something was done incorrectly during the service. (My brother once ended up driving sixteen hours without heat in the dead of winter after some last-minute service went wrong.)