The three NFC West teams reaching the Super Bowl over the past eight seasons had an important similarity.All three kept their offensive lines intact all season.That is the case for the San Francisco 49ers as their linemen -- left tackle Joe Staley, left guard Mike Iupati, center Jonathan Goodwin, right guard Alex Boone and right tackle Anthony Davis -- have started all 18 games together heading into the Super Bowl.The 2008 Arizona Cardinals and 2005 Seattle Seahawks reached the Super Bowl with similar continuity along their lines.