Somewhat.
I'd wager that there are some enormous differences in California. Everyone believe CA is all flowers and rainbows, trust me, you go 50 miles outside (say) the Bay Area and you run into vast areas of intolerance to those ideals. Likewise, you can be in the Carolinas and find some of the most progressive pockets in the country.
I firmly, firmly believe that the stereotypes are jacked and maintained to create and maintain splits. Essentially (for me anyway) what I see is that wherever there is more manual/physical labour-based employment, poverty is greater and anger/frustration greater. I do agree it has extremes, and I'd add I think it's important for those not in it to remember it is essentially the size of a continent, and several states are larger than most European countries. So in that sense, absolutely there will be (essentially) cultural differences.