https://bugs.winehq.org/show_bug.cgi?id=39891
--- Comment #21 from Omar gamingpakker+wine@gmail.com --- I've checked in Windows (dxdiag) and it seems that it does not assign unique names. Both controllers show up as 'Controller (Xbox 360 Wireless Receiver for Windows)', however, it does assign a unique controller ID (in my case 0 and 1 respectively).
For me I think the mapping to the last entry was because the controllers were all duplicates; I've not used more than 4 controllers (I have only 2 physically available to me and the receiver doesn't handle more)