Usually "up to" means that if your battery has 1,000 cycles or fewer and has more than 80%, your battery isn't defective. While 87%/~50 cycles might seem alarming, you have to remember that the rate of decay isn't strictly linear.
That being said, I think if you were very polite and explained your concerns to a genius, they would probably be willing to help you if they were in the right mood. It's really hard to predict of course, because each genius has a different temperament.
I assume by your OP that you have no Applecare and that you bought this notebook on September 7th of last year. Did you buy the mbp, IN FULL, on a single credit card? If you did, you may want to look into your credit card company's extended warranty policy. My Mastercard, for instance, automatically extends any warranty for computers and phones by an extra year at no cost (it also usually doesn't require registration, just proof of purchase). I mention this because if the battery continues to worsen, and the mbp is out of warranty, you might be able to get your credit card company to cover the cost of the battery. Look into all of these factors before deciding to make the trip by the 6th.