If the AW battery health is slightly above 80%, I have heard of people being able to get the $79 "battery service" (which is actually a new or refurb watch).
But if it is like 90%, Apple will generally refuse, for an AW. They refused for me, when mine was at 85%. Reason is people have abused it - they get a scratch, then go in and demand battery service, and basically get a replacement watch for $79. Apple is not that stupid - they lose money on these "battery replacements" - certainly a lost opportunity cost, if not anything else.