No. Mozilla has never had any Releases in packages like .rpm or .deb. If they were going to use something beside the simple to use tarball, it would have been autopackage. The problem with packages not made for the distro is that dependencies and different dependancy names across distros for same thing can be a pain in the but as a result.

Some years ago I remember there was talk of making a place for people to check in finding packages made by they Linux distro though that never happened.

They did consider .rpm builds for a time but it stalled out just over two years ago. For reading as bugzilla is not a discussion forums and not useful comments are bug/email spam.

Bug 649721 - [tracking bug] RPM Packaging polish Bug 600317 - Fedora/Firefox - Repository setup for Firefox nightly and aurora

Bug 277066 - Toolkit apps need to provide .package (autopackage files) for different linux distro users

Note that most file managers on Linux are able to open such archives with a double click and you can use copy and paste to copy them to a destination folder. You need to start the file manager with root privileges if you want to install Firefox in a location owned by root. I usually install Firefox in a folder in /usr/local/