Archlinux has 67.0.3 already. Some mirrors are still not updated with it, but the one on kernel.org is. Just put that mirror on the top of the /etc/pacman.d/mirrorlist file before running sudo pacman -Sy firefox.
Gentoo also seems to have updated firefox-bin (and possibly www-client/firefox too?)...I ran an emerge update a few minutes ago and saw it install the firefox update