Not that I can see (you got me all excited!) . The size of the 51853 patch will vary based on how many files need updating. If you have any mods, or didn't download the previous build, the total size can change.
It's was commented on reddit: http://www.reddit.com/r/planetaryannihilation/comments/1kfntz/a_secret_update/ It's should fix d3dx9_43.dll missing error for future Steam users.
Damn it, got excited for a second reading that. So psyched for the next patch (Whatever it may be -fingers crossed the beginning of orbital)!
