Yes No and Maybe
Rumor has it the Texas fab"green"is now using copper. Since the other rumor is that 900(or maybe higher)and above need copper. People have reported 1.2gig green core(red,purple and brown too)so they ...must be using copper???Germany seems to keep the blue dye in good stock so no odd colors

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What does all that tell you,nothing.
The blue cores did seem to OC better but when you want a CPU to do more than it should its all a crapshoot. If you pass up a CPU by the core color you could be passing up some freakish OC monster,or you can play with the odds in your favor......BTW 700@1gig is a good one if you can smooth it out.

Hope it goes well.......Clock On