That is a good question.  It looks like a complete package (die, heatspreader, substrate).  If it was only the die I would expect it to be bare silicon (has a rainbow sheen).  While I guess each die could be packaged independently and then all four attached to a substrate that doesn't make any damn sense.  So my first thought would be it is a complete package but it would appear to be too small, and not match expected characteristics at all.  I would be expecting a shiny metal lid, substrate which extends out from beyond the lid, and no writing on the package lid.   The lid is going to be the primary thermal transfer so it would be designed for high conductivity.

For example: KNC board. 
http://www.alchip.com/uploadfile/201311/20131105093923760.jpg
Big shiny in the middle is completed package (which also contains 4 dies like HF design although at lower throughput).


So based on the single photo alone it doesn't look like a completed package (4 dies + heatspreader/package lid + substrate) and it also doesn't look like a bare die either.  So

Some more and better photos (from side and bottom and with size reference) would help.