The initial soundtrack release of Metro: Last Light only contained 46 tracks (which is the version you can find on the forums), leaving the 64 track version a Sumthing exclusive. However, a few months later all digital stores were allowed to carry the 64 track version and the extended release is now the default release.

Does anyone have the 64 track version of Metro: Last Light OST?

I'm looking for it too.

But the shorter one on VGMdb (http://vgmdb.net/album/40726) has 37 tracks, not 46.