Yes. Kurt Russel's mustache in the film Tombstone is real.
Tombstone is unique in that almost all of the mustaches are real except one guy, Jon Tenney (as Sheriff John Behan).
According to this source, he didn’t get to grow his own mustache because he had a job right before that. They had to put a fake mustache on him.Because it wasn’t his real mustache, he had to take his mustache off everyday.
If there were awards for the best movie mustaches, Tombstone would win them all, according to People.com. Written by Kevin Jarre, who had previously penned the civil war drama Glory a few years earlier, the 1993 Western revolves around Wyatt Earp and his brothers Virgil and Morgan, who arrived in Tombstone, Arizona at a time when it was plagued by a group of outlaws known as The Cowboys.
Based loosely on the true story of the Gunfight at the O.K. Corral, Kevin Costner was originally going to star, but he disagreed with Jarre over the script and decided to make his own movie centered specifically on Wyatt Earp.
1994’s Wyatt Earp, released just six months later, covered similar ground, but was no match for Tombstone in the facial hair department.
Know more info about Tombstone by reading this post: Movember Movies: Tombstone (1993) from FilmJunk.com.