Cannot see old read email after backup restore

Customer deleted old email in "/cur" for his account, so asked me to restore. I did the restore and I now see 3000+ emails in cur, but customer claims inbox only has new email, not the older, already read email that I just restored. I used the normal internal cpanel backups restore option to do it. Is there some tweak/fix I need to do to get the restored email to be seen by the customer ?