There's no config option for it, but it's theoretically possible to do just about anything. Generally, though, the format of those filenames is defined by the Maildir standard. Changing the filename as you suggest would likely break other mail programs that might access those Maildir folders.

I suppose the question is: why would you want to change that?

My company's current system (unfortunally) uses that non-standard format. The MTA writes in that format.

I guess it would require a patch then?

tks. gpg