Having run a backpackers in the UK for 6 years and having dealt with guests of various ages I can offer you a few views...
Yes definately. The younger ones are often more concerned with partying and bed hopping than doing touristy stuff; but this depends on nationality somewhat. The young British are, by far, the most prone to drunken, noisy etc.. antics.
There are different types of oldies... and there are different forms of backpacking - short trips and long term travelling. Two types of oldies come to mind... there are the 30 somethings that keep travelling because they are in denial, can't accept mundane real life, cannot find a partner and cannot accept the fact that they are getting old. Then there are the ones who's kids have left home and they are taking the opportunity to do what they always wanted to do, but could not when they were young. Some of them land up rather disappointed when they actually do it
It may sound a bit cyncial, but it's quite close to the truth.
I can't imagine anyone being happy to be called a Greypacker!.