Does the facebook pixel match external_id's with other PII retroactively

If a user I have no information about enters my site and I generate a uuid for them to send along with their pixel event as the external_id and also store it in a cookie. When they later log in or register and I start sending advanced matching parameters like names and email, if I also send the external_id parameter will Facebook retroactively match the events prior to log in or registration with the user?

https://stackoverflow.com/questions/66792052/does-the-facebook-pixel-match-external-ids-with-other-pii-retroactively March 25, 2021 at 10:05AM