FYI the Z refers to the batch it was processed in. The rest of the information on that line is the serial number. The old rule of thumb was latter batches were better OC'ers and that is why Y is so popluar, Z is actually a fairly rare batch assignment.
Not that it hasn't been said before and probably isn't in a million stickies, but just in case:
1st Line: AX1600DMT3C
A=Family/Architecture: A=AMD Athlon(tm) XP Processor Model 6 Architecture
X=Generation: X=High-Performance Desktop Processor
1600=Model Number: 1500 operates at 1333MHz, 1600 operates at 1400MHz, 1700 operates at 1467MHz, 1800 operates at 1533MHz, 1900 operates at 1600MHz, 2000 operates at 1667MHz, 2100 operates at 1733MHz
D=Package Type: D=OPGA(Organic Pin Grid Array)
M=Operating Voltage: M=1.75 V
3=Die Temperature: 3=90 Centigrade
C=Max FSB: C=266FSB
2nd Line: AGOIA 0226WPAW
AGOIA=Stepping
02=Year: 02=2002
26=Week: 26=26th week
WPAW=? Non relased information
3rd Line: Z1514282258
Z=Batch: Z=final batch, batch order 1-9, A-Z
1514282258=Serial number
AMD uses most of the undisclosed information for tracking. I have personally spoke with several AMD engineers and they are very proud of the ability of their product to OC. Check out this link,
http://www.amd.com/us-en/Corporate/AboutAMD/0,,51_52_3592_762,00.html I had about a 2 hour converstaion with the field engineer from my local AMD office, he was very friendly and helpful and they love to chat about their products, why not give your local guy a call...
About the color: The color has nothing to do with the quality of the product or how it will perform, or even when it was made. Color is subject to where it was manufactured and what materials were available at the time. Truthlfully while most of us are familiar with green or brown, there are almost a dozen variations within these two colors, hues, coatings, tints, etc...
The bottom line will always be, HOW WELL DOES IT OVERCLOCK FOR YOU!