i think i just answered my own question with a little more investigation. i see from an older article of tom's that the Dresden (fab30) chips (the copper ones) have a blue-ish tint to them. Mine does and looks a lot more like the blue one than the green one in the article. hopefully, i'll get this thing past a gig.
Yep blue ones are copper. Oddly I too thought the green ones were copper, thats what caused me to check myself. In the first review of the Tbirds there is a pic comparing the old slot A althons to the Slot A Tbird and both have green cores, aka aluminum cores. Dont make sense to me, would think copper is green and aluminum blue but thats not the way its works!
Given what it physically looks like, I am inclined to believe it is Copper (fingers crossed). The markings are exactly like what THG purports to be a copper chip. Now, I suppose I could always have purchased a copper chip that actually will only run at 850, but we'll see. Believe it or not, I actually was sidetracked last night and stopped building the system midstream... now THAT's a first for me!
One thing I noticed in putting this thing together was that the heatsink included, while looking pretty good, was anodized (colored) and the bottom was not very smooth. So, I sanded it down to the bare aluminum with some fine grit paper.