The only other time Allen raised the flag was before the 2005 NFC championship game when Seattle beat Carolina 34-13 for its only Super Bowl trip.
As he did the previous time he raised the flag, Allen walked to the railing and waved a towel exciting the fans before kickoff.
He also accepted the trophy from former owner John Nordstrom after the 23-17 victory over San Francisco on Sunday.
HALFTIME SHOW: Seattle rapper Macklemore performed during the brief halftime. Instead of getting a stage on and off the field, a stage was erected at the south end of the stadium on the second deck. Macklemore, friends with Seahawks coach Pete Carroll, wore a Seahawks jacket from the 1980s before taking it off and revealing a current No. 12 Seahawks jersey with his name across the back.
Macklemore, nominated for seven Grammy Awards last month, performed two songs off his album "The Heist." He said he'll be postponing a planned trip to India in order to go to the Super Bowl and watch his hometown team.
"It's about the Seahawks, it's about this win, it's about us going to the Super Bowl," Macklemore said as he celebrated in the locker room after the win. "There was a lot of highs and lows throughout the game and we came out on top. I'm so excited for this team and so proud of these guys.
STATS: 49ers QB Colin Kaepernick rushed for a team-high 130 yards, 98 in the first half, but passed for only 153. His QB rating was just 56.4, and was almost doubled by Seattle's Russell Wilson (104.6).
Frank Gore managed only 14 yards on 11 carries, matching his low for the season. He had 16 yards at Seattle in a Week 2 loss.
Doug Baldwin led Seattle with six catches for 106 yards and had a 69-yard kickoff return. Marshawn Lynch rushed for 109 yards, including a 40-yard scoring run. He has four 100-yard performances in six postseason games.
Seattle has won seven straight home playoff games.
Before he left in the fourth quarter with a severe left knee injury, All-Pro linebacker NaVorro Bowman had 14 tackles and a sack. LB Aldon Smith had two sacks.
For Seattle, LB Bobby Wagner led with 15 tackles.
RECORD CROWD: Seattle set another stadium record with 68,454 tickets distributed for Sunday's game. It was the second straight week with a stadium record after setting a mark with 68,388 for the divisional playoff game last week against New Orleans.
BRING ON DENVER: The Seahawks trail the all-time series with the Broncos 35-19—Seattle was in the AFC until 2002. But the Seahawks won the only postseason meeting, 31-7 in 1983 at the Kingdome in Seattle's first playoff game.
Denver lost 40-10 at CenturyLink Field in the preseason last summer, when Peyton Manning went 11 for 16 for 163 yards and a touchdown.
The Seahawks are 0-1 in the Super Bowl, having lost to Pittsburgh after the 2005 season. Denver is 2-4 in Super Bowls and has not been there since winning a second straight time after the 1998 season.
NOBODY LEFT: Seattle will go to the Super Bowl without anyone left over from its only other trip after the 2005 season. The roster turnover has been massive under Pete Carroll and general manager John Schneider, with only four players remaining from before the pair arrived in 2010 and no one who has played in a Super Bowl before.
Mike Holmgren was Seahawks coach that season and relied on a precision offense led by quarterback Matt Hasselbeck and league MVP running back Shaun Alexander.
Holmgren spoke earlier this week about his reverence for that 2005 team.
"I'm emotionally attached to those guys and I love those players and I love those coaches and I think they accomplished a great deal that year," Holmgren said.
HARBAUGH'S PAY DAY?: Jim Harbaugh just completed the third year of his $25 million, five-year contract with San Francisco by becoming the first coach in the modern NFL era to lead his team to the NFC championship game in each of his first three seasons.
While Harbaugh refuses to chat about a contract extension or what kind of job security he might want, CEO Jed York is eager to sit down with his head coach and talk about the future.
Many figure Harbaugh will receive a hefty raise. Not that it's a priority: He wants a championship ring with the men he has grown to love.
Were his players road weary by the NFC title game following wins in Green Bay and Carolina the two previous weeks?
"I didn't see that from where I'm standing, no," he said. "It was a 15-rounder from where I was standing."
AP NFL website: http://www.pro32.ap.org