PowerEdge R320 fan part number(s)

I am trying to determine what the correct part numbers are for the five fans within a PowerEdge R320.  I have three servers to examine and all had fans which differed both in Dell part number, amperage (1.2A, 1.5A, 1.83A), and manufacturer (Delta, Sunon, etc). I searched the Dell part finder tool and the owner's manual to no avail. 

Thus I am trying to answer the following questions:

1. Are all five fans on a R320 identical/interchangeable?  I am assuming yes, but wanted to clarify.
2. What is the correct Dell part number for the fans on an R320? (or numbers if they differ by position e.g. fan-1 vs fan-2)

Any assistance in answering these questions will be greatly appreciated!