In the way that it's used now, yes. The Cowboys of the early 90s are considered a dynasty, etc.
But they're not in the same category as the Celtics, Canadiens, Yankees, etc. They're not even with the Steelers, Oilers, 49ers, Pats, etc. You need dominance and longevity, and four years just isn't enough.
But, I have no doubt they'll hang another couple of banners.