If it has the thick boss were the bolt goes to mount the throttle cable bracket like this one it's a PTE. If it's the same thickness all the way around the base it's a accufab.
Richard Clark tested all the plenums a few years back. Don't know where the PTE came in, but the Hemco was the winner. So much so, that it is rumored to be being re-tooled as we speak. Several guys searching for them all the time. No power plate needed, and they were built with a 1 inch spacer designed into it.
No idea. I was buying a used one from a non board member and he was involved in it...somehow. I was given his number but it was a year ago. I hope it really happens