Hello - I am trying to understand what the meaning is behind different versions of DELL server motherboards (i.e. SYSTEM BOARD, PWA, PLANAR, MOTHERBOARD, V2, DELL R620 - part number KCKR5, vs. SYSTEM BOARD, ASSEMBLY, PRINTED WIRING ASSY, PLANAR, V4, DELL R620 - part number GFKVD).

Are these two boards interchangeable, or is there a specific set of circumstances under which each must be used? And if there are differences, is there a process to make them functionally equal under all circumstances?

Much appreciated :)