Also I didn't realize this until last night when I checked, but the Panthers had the easiest schedule in the NFL this year. They played the AFC North and NFC West divisions, as well as playing within the terrible NFC South division. Now they did play extraordinarily well in the playoffs so they are obviously a good team, but perhaps the 15-1 record was more a product of schedule than being the legitimate best team in the league?
In short, most definitely yes.
http://fivethirtyeight.com/features/the-panthers-are-the-worst-team-to-ever-start-11-0/
Pythagorean wins is another good way to measure how many wins a team "should" have, though it is less effective in fringe cases. The panthers outperformed that by ~3 wins, which is pretty significant but not entirely damning.
17-2 is an elite record, no doubt about it, but of the likely dozen or so teams that have finished 17-2 or better it is likely that the Panthers end up as the "luckiest" or "worst" or whatever you want to call it. Still, they were one of the only great teams in the NFL this year, and in my opinion the only great team past December. They are still more on par with the 2013 or 2014 Seahawks than the 2007 Patriots or 85 Bears that there were at least some allusions to in the broadcast, though even that might be too lofty.
Obviously it is way too early to predict (as if that would stop us) but assuming they keep most of the same core in place a regression of a couple wins from "elite" 15-1 to "great" 12-4 should be expected for them and any similar team that drastically outperforms their expected win total.
Side note: Denver also outperformed their Pyth wins by an almost as impressive 2.3 wins, as did Min (1.2) and Ind (2.0). Seattle actually underperformed theirs by 1.8 wins. This method was within 1 win of almost every other team in the NFL, per football outsiders.