Your PC will come with 4G of RAM 2x2G and you want to add 8G more 2x4G for a total of 12G.
Based on the links you have provided, yes it will work.
Worst case, if you have any trouble with stability, take out the 2x2G and leave in your 2x4G. Sometimes PCs have stability issues if the ram is not the same amount per slot. 8G of Ram should be enough for nearly every application.