I don't know what relationship www.keurig-k-cups.com has to Keurig, but that is definitely not the official site. Keurig (www.keurig.com) does answer a gluten question on their FAQ page concerning coffee but does not mention tea at all:
Do any of your K-Cups contain gluten?
Answer
All of the coffees offered in K-Cups are gluten and gluten byproduct-free...