We have a handful of HP dc7700 workstations and just about 100 HP dc7800 workstations. The machines are newly deployed and should have latest firmware and drivers. I've checked and the AMT service is running on Windows. Now I can't tell you for sure if it's enabled in BIOS or in the ctrl P because I hadn't been aware those were options 
I'm going to read up on the guide you linked and I'll be checking a couple of our workstations for what you had mentioned.