I went to the first lecture for FINC2013 this semester, but ended up doing Corporate Finance II instead.
If I remember correctly, 2013's mainly involved with the process of deriving the CAPM.
From the way the two units are presented, it makes it look like 2012 and 2013 are interchangable, however they cover much different areas. I spoke to the 2013lecturer (Max Stevenson) after the first session, and I think he put forward that FINC2012 was probably the more important unit to do, but he did recommend doing both at some stage.
I'm doing FINC2012 atm, however if I have a spare unit in 3rd or 4th year, will try and do FINC2013 as well