If someone sends me their stamps, and I plant a series using their stamps, that's not an adoption, is it?

No, it's not. Adopting is when you take over someone else's box, a box planted by another. You have to have permission from the owner to take over the listing on AQ. On LbNA, there are boxes available for adoption that have pretty much been determined to be abandoned.

Sometimes people will unofficially adopt boxes by maintaining them, but that isn't your situation, and it doesn't give them access to the clues to make changes.

In this case, you list yourself as planter and list who carved it when that option comes up.

The glossary has much of this information, for future reference.

Yes, that's what I thought. Thanks.