It's NOT good to mix RAM even of the same part number. Two kits might work or might not. There is no means to know other than trying it. That's why I always recommend buying ONE matched, tested, RAM Kit.
Yes, those kits should work without a problem. Although what the person above me said can be true the technology used in the type of memory you are looking for is a lot less sensitive than new high speed RAM and I highly doubt you will have any problems.
Back before I knew what I was doing I mixed brands, sizes and all sorts of things with that kind of memory and it never had a problem.
I'd recommend using only 2 memory slots. The older machines did not liked all mem banks occupied for some reason.
Also DDR3200 should work as 2700 but you will have to downgrade it in the bios if possible
otherwise get 2700.