Does changing regional timezone settings alter the “Modified” and “Created” fields on every list to fit that new timezone?

I realized that I was entering data into Sharepoint when the timezone settings was PST rather than EST. I changed it, but now it’s taking a while for the automatic datetime fields (“Modified” and “Created”) to reflect that change in the lists. I really do not want to have to reenter all my data so that they reflect the new standard.

I’m not just asking about new entries, but also entries that have already been made.