capilene 3 top weighs only 6 oz?

Well, Mr. Don T. Juan II,

For what it's worth, I happen to be wearing a well-loved(worn) Capilene 2 zip-neck in a size M and just took it off to throw it on my scale here: 7.8 oz.

Last time I checked, the Cap 3 was basically a bi-component mircro-fleece with higher "pile" than the Cap 2, which is definitely thinner, but with a more obviously differing texture between the inside and out.

Interestingly enough, Patagonia.com lists their weights as Cap 2 Zip T = 6.1 oz. / Cap 3 Zip T = 7.8 oz. Thus, reasoning empirically, I must conclude that I have your pullover, and you have mine. :) Mine is most certainly Capilene 2, but it is likely an older style than the current one. At least some manufacturers lighten up over time, even while increasing recycled content, Ahem.

http://www.patagonia.com/web/us/product/patagonia-mens-capilene-2-zip-neck?p=44850-0-029&pcc=1128

http://www.patagonia.com/web/us/product/patagonia-mens-capilene-3-zip-neck?slc=en_US&sct=US&p=44440-0-685

Looks like mine is indeed a Cap 3 Zip-neck and does weigh 6 oz.. but it is the women's size medium. That's the weight listed on the Patagonia website.. I bought this on clearance from backcountrygear.

You are right.. the inside does look different from the outside. But the layer (white) doesn't look anything like the pics on the Patagonia website which make it look like a heavy fleece. This is a somewhat thin 'clothy' material.. smooth without that fleece texture.

Might still be warm though.. debating taking it with me as my only layer (besides a hiking t-shirt) on a thru-hike of the Colorado Trail in August along with a 14 oz FUGU down jacket.

I would think a Fugu overkill for the Colorado Trail in August, but you certainly wouldn't be lacking for warmth. I would consider a lighter weight down option that you could use for early AM hiking as well as around camp. The Cap 3 dries more slowly than others, but makes a nice mid-layer. I've been happy with mine, but don't use it on UL endeavors. My choice would be: Lightweight Merino base, Montbell Ex Light mid, wind breaker, shell, + Ex Light Vest or Inner Parka for variable conditions down to upper 20's. Pushing deeper into the 20's and I'm all for the Fugu. It would likely make a fantastic camp pillow, though.