Not yet, but he is well on his way. It is easy to say 'yes' as his first title is still less then 24 hours old, but I do not think he is quite there yet.
I think it may lock it up. I was of this exact mindset until I started lookig into the numbers... for example :Cowher vs. Parcells
Cowher 153 wins, Parcells 174 wins
Cowher .627 winning percentage (incl. playoffs) - Parcells .572
Cowher 12 playoff wins Parcells 11
Cowher 10 playoff appearances, Parcells 9
Cowher 8 division titles, Parcells 6
Cowher 11 winning seasons, Parcells 12
Cowher 6 Conf. Championship appearances (2 wins) - Parcells 4 Conf. Champ. appearances (3 wins)
Cowher 1-1 Super Bowls, Parcells 2-1
Considering Parcells is considered one of the best coaches ever and a mortal lock for the HOF, Cowher is in pretty good shape, especially when you consider he's coached 4 fewer seasons than Parcells. He's only 21 victories and 1 winning season behind him, and already has the edge in division titles, playoff appearances, and conf. championship appearances. He's still 1 SB trophy behind the Big Tuna, but aside from that, I think his resume shapes up rather nicely.