Why on earth would anyone give this rumor any sort of merit? With the current cost of macbooks, I can’t see them hogging a case out of a solid piece of aluminum, further increasing production costs.
More likely than not, someone taking a snipit grossly out of context. It is not unlikely that a portion of the frame would be Al. Heck, Audi used large single piece aluminum frames to hold up the kick panels in my B5 :shrug:
I would think a family of dies to cut and stamp them would be $60,000.(Not really my expertise but probably not too far off)
You could machine quite few from billet/plate for that kind of coin, especially in China where they are most likely assembled.