If you've got a good, close group of friends from childhood then I think it definitely makes it easier to make friends as an adult as you always have that group of friends so there is less of a need to make new ones, which in turn makes someone more sought after.
People just seem to warm more to someone who already has lots of friends.
We moved areas when I was 12 and left my childhood friends behind. I had to start at a new school where I was bullied and so didn't leave school with a core group of mates. I have friends I've made in adulthood but it's been hard at times, as everyone already seemed to have a best friend, and as I mentioned upthread, people aren't that receptive to those that don't already have lots of friends.