I had to check out that 'pcm' reference. interesting...
I had to check in my hobby room to verify i still had one of the 'milled' chassis in the lineup. Mine is a "dragon" of of ebay. They were the rage in our group for a while but didn't turn out to be that 'bulletproof' in crashes. They are milled, have etched dragon name and are black, not gunmetal color. (went up from $38 to ??)
Latest car i'm running is the 777 that requires you to mill out for 2 speed and use the 777 steering top plate over the different bolt spacing for steering supports and the 777 ackerman link. (smooth, not milled out)
I don't have a link for the milled 777 you're looking for. Every once in a while i'll see a reference to a 'special' version but i think those might be rare.
The dragon is similar in looks to that 'half 8' on the pcm site with the milled out sections.
You might be after a special edition 'kanai' or such.