Mautic contact import merge question: Existing Do Not Contact?

We want to import contacts from a different DB into Mautic.
Basically those are webinar users that now will also use mautic.

What happens, if couple of contacts (that will be imported) e.g. a,b,c are already in the Mautic database and do have DO NOT CONTACT im Mautic active?
I assume that those contacts a,b,c of the external db will be merged with the existing ones a,b,c of Mautic. Will the import leave the Do not contact of Mautic active?
This would be important as of GDPR/DSGVO.

Anyone had this case?
Thank you!