While A Numbers are sometimes used for other visas in your life .. sometimes a new A number is issued during by the process. We provided our initial A numbers ( from a previous GC through work) during our later IR5 applications, but were issued a new number anyway. They already will have you and your existing number matched so I don’t think there is anything you either can or need to do. Moving forward through N400 , we used the most recently issued A numbers. No problems incurred at all