As many have stated, pay $10 for TW to match a set. Or, carry a scale and measuring tape to your local pro shop and make sure that at least the balance and static weight are matched. You could even use the iPhonw swingweight tool to match the swingweight.
My last Wilson's were purchase without matching and the balance was exactly the same and the static weight was less than 3 grams apart which is over 99% match. I did ask the pro shop to check the weight and balance before I bought.