I have a puzzle for my many fellow tennis maven colleagues. I purchased 3 of the same racquet (a Wilson nCode 6.1) over the period Wilson was producing them. I bought 2 at an earlier date (~2006) and one later (~2008). I am now changing to the BLX variety of this stick, but am only purchasing 2 right now. For this reason, I'd like to keep the newest of my nCodes. So here's the question: Can anyone suggest a tactic for effectively dating these racquets? I've rotated these, so the wear is about the same. I've also contacted Wilson and the merchants from which I bought the racquets. No luck. Some thoughts - is there any information that can be gleaned from the holographic sticker on the frame? Or the stamp on the buttcap? Any ideas here would be much appreciated!