All 5 fans of R320 are identical and interchangeable.  It is recommended to have all 5 fans with same part number. HR6C0 and G8KHX are some part number for R320 fans. 
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: Any assistance in answering these questions will be greatly appreciated!    
PowerEdge R320 fan part number(s)