Can I exchange parts between a MacBook Pro 2011 early and a late one?

Yes! The two 2011 runs are using the same hardware.

The best way to think this is looking at the series ID string. So looking at yours MacBookPro8,1 we can see all of the different CPU options Apple used which is the only difference in the 13” models.

In the 15” 2011 models MacBookPro8,2 there is also a discreet GPU which is either a AMD Radeon HD 6750M or 6770M, otherwise its the same hardware.

FYI: In one of the rare cases Apple used the same hardware in the 2012 models! The 13” MacBookPro9,2 and the 15” MacBookPro9,1

The logic board now offers USB3 over USB2 between the 2011 and 2012, and if you transplant a 2012 logic board into a 2011 system you need a slight modification to the displays LVDS cable to make it fit the socket.