The Niners will be wearing their throwback uniforms on Sunday, and members of the team have been inspired by photos of the team's greats -- many of them sporting facial hair -- displayed at the team's facility in Santa Clara, Calif.
The offensive line initiated the effort, and quarterback Shaun Hill has joined in.
"Today is Mustache Monday," Hill said of the effort, according to the San Francisco Chronicle. "It's for the throwback game. Every day we go to meetings and we go by these beautiful pictures and we admire these guys' mustaches."
According to the report, the team's facial hair gallery of greatness includes Kevin Fagan, Mel Phillips, Roger Craig, Ray Wersching, Keith Fahnhorst, Jerry Rice, Jimmy Johnson, the late John Ayers and Randy Cross.
"Every single day that we walk through here, you just can't help but admire John Ayers' mustache. It's awesome," Hill said, according to the report.
Hill's mustache, however, is not yet up to those lofty standards. "I started four weeks ago. How bad is that?" he said, according to the Chronicle.
In other 49ers news, running back Frank Gore plans to return to practice this week with hopes on playing in Sunday's season finale. Gore is just 22 yards shy of becoming the first running back in 49ers history with three straight 1,000-yard seasons.
Information from The Associated Press was used in this report.