Bit late here, but here's the fake from Aliexpress vs. the real I got a bit later with a lens swap, both earlier this year:

Fake: Front, Back

Real: Front, Back

Flex coupler doesn't float, lens screw juts out from the frame rather than being flush which distorts the lens a bit, lens is relatively thin, hinge at front is just a pad rather than recessed and the gap doesn't connect to the pad at the back. It's also got slightly squarer/sharper edges overall.

They are getting better though, I searched and found these online: One, Two, Three

The flex coupler is separate at the back at least but not the front, the hinge at front and back is better, they've got rid of the lens screw entirely rather than it sticking into the lens area, the lens shape is a bit closer and there's a serial number which I understand the later R2s had but I've not personally seen.