More or less. qmail does it with hyphens. See my from address.
Believe
qmail actually calls them "extension addresses." Had to look that up.
Wouldn't be surprised that Postfix did it, but differently. Maybe there's
compatibility in there samewhere. Will look into that when have time.
All of this is pretty irrelevant. Don't expect Fedora or Redhat to ever
support qmail, and can certainly understand not doing it. At the time qmail
was started here, it was a better alternative than sendmail, and there
weren't that many choices.
postfix can do this too with regexp for aliases.
-sv