I agree that for purpose of thi example you do need to say ignore=yes. However regardless of this parameter it will not overwrite existed procedires because export file does not have create or replace, it only has create statement.

I did create a user and create procedure under this user schema and actually browse dump file and did not find create or replace statement.

Conlusion :

You have to drop all your procedures and function, otherwise it will not replace existed procedures, but will bring new ones and results will be difficult to reconcile.

Just want to mention that was a schema level export and full database export could work differently