mdbox vs. maildir format

[Marc]

> 
> "Note that with dbox the Index files contain significant data which is
> held nowhere else. Index files for both sdbox and mdbox contain message
> flags and keywords. For mdbox, the index file also contains the map_uids
> which link (via the “map index”) to the actual message data. This data
> cannot be automatically recreated, so it is important that Index files
> are treated with the same care as message data files."
> 
> https://doc.dovecot.org/admin_manual/mailbox_formats/dbox/
> 

Say you lose the index files. Is it not possible to 'script' the 'm.988' files, so all messages are in mbox format and then convert them back to mdbox?
To me the most important part of the email is the sender and what and when he wrote it. I don't even use flags, and I am not sure what keywords is about.