iPhone 5 sleep/wake button replacement?

Today, my iPhone 5 was taken to an authorized service center (iShop) for repair due to a problem with the sleep/wake button. Fortunately, it was accepted for repair under Apple's program, even though it's almost two years old. The advisor told me I would receive a new one in 5 days and that the part would not be replaced. I want to know if this is true and also what Apple does when they receive my device. Thanks in advance!