Nest20,   That part number and part are correct, and the cables for the 2 socket would be part number FJYF0 (left) and FYPFK (right).    
I would like to add NVMe drives support for my R940 server (we have one with with 24x2,5" SATA/SAS drives backplane). I found this video about installing NVMe cards and cables for R940 server:[URL] I've also checked backplane in my R940 server - looks like it has all the connectors shown in that video. So, I'm looking for part numbers of the cards and cables shown in that video because local DELL seller can't find them  
Add NVMe ssd support to R940