Understand.The play store version was never installed. As mentioned before, I was always using the version you can install with toolbox. It's just that that version was outdated (see Datastreams comment about that above).
So regardless of source, you have updated Netflix so that it is now recognized as an updated Amazon app. That's great.
Still, as a precaution, check Netflix in Play Store to ensure that if there is a listing for Netflix app it is set so auto-update is disabled; sometimes Play Store "polls" your system and finds an app downloaded/updated from AppStore and recognizes it as a Play Store app and tries to update, causing "update clash" . Precautionary chek , not a big deal.