Hi Santiago
http://www.cisco.com/c/dam/en/us/products/collateral/servers-unified-computing/ucs-c-series-rack-servers/c220m3-sff-specsheet.pdf
The only thing I see is:
NOTE: In a two power supply server, both power supplies must be identical
I think this note refers to e.g. mix of 650 and 1200 W PS is not supported..
But UCSC-PSU2V2-650W is definitely the follow product of UCSC-PSU-650W and therefore no problem.
http://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/c/hw/C240M4/install/C240M4/spec.pdf