You're correct, the board you have at present is a v3. I'd try to replace it with a v7 board, but if all you have available is the v4 board, then that's perfectly OK.
Good morning, what is the difference between the various DP / N numbers on the poweredge R720 motherboards? can i replace my card with others even if the numbers are different? I have to replace my VW90T motherboard with a 0C4Y3R can this be done? thank you all    
Difference between DP/N numbers motherboard Dell R720