Yes. My understanding from conversations with those in the know, and our limited testing at AMP launch, is that you treat the CDN as a proxy. All the downsides of losing visibility to your domain and none of the upside from offloading traffic.

That being said, we did notice some single digit percentage traffic bumps when we rolled out AMP, and it felt really good telling the hordes of product/business people that I literally couldn't add the dozens of analytics scripts they wanted.