From the 2001 Bass Player magazine:
BP: Are you still playing your '72 Precision?
AC: I am. It's got a bit less varnish than it once had, but it's still around. I see photographs of it from different tours, and I can see the varnish gradually wearing off. It's a really light instrument, which is fantastic, because it's got this nice brightness without losing any bottom end. I'm always changing something on it, but it's still pretty much the same instrument I've always played. I did put a Jazz neck on it very early on; I find the Jazz neck suits my left hand better. The Precision is a painful, physical thing to do battle with. The Jazz is a bit more ladylike.
- The whole article can be found at: http://www.u2-stage-and-studio.com/adam/id12.html
But judging by this picture I found... you can see it did have a Precision neck at one point during Elevation:
The above picture being from closing night of Elevation, in Miami.
His main Precision is referred to as a 1972 in the 2001 Bass Player article (as seen above) but is referred to as being a 1973 in the 2006 Bass Player feature article.
http://www.u2-stage-and-studio.com/adam/id13.html
BP: Do you get emotionally attached to the instruments you play?
AC: Not really. I have a ’73 Precision Bass that I’ve used since day one. I used to think, This is the old work horse—old faithful. I loved it. I still love it, and I play it all the time, but I try to branch out and play different instruments. I’m not so attached to any of the others. I’ll play them for a bit and then move on. But there’s an amazing difference with vintage basses compared to regular stock instruments. I love finding instruments that have had a life before you got them. They bring something to you.
... 
. Anyway, its probably a lot less than the Korg A3, and I can get a perfect sound out of it. Obviously, it does a lot of other amazing things too, but I never expected that out of it.
