I can't imagine that the person you identified ceased to be the same person just because their DL expired. Just saying.
This has been my reasoning too, but this is one area where I anticipate that I might be challenged by an examiner based on the way the FAQs are worded:
"...a financial institution may rely on information in its possession to fulfill the
identification and verification requirements, provided the existing information
is up-to-date, accurate, and the legal entity customer’s representative certifies or
confirms (verbally or in writing) the accuracy of the pre-existing CIP information."
If "existing information" refers to their personal identifying information, great, if it refers to the information collected from their identification, then my procedures are wrong.
Common sense is on our side, hopefully that means something.