Using CMS account we can download raw data files from youtube(https://cms.youtube.com/cyc_download_reports). This csv does have information whether a video was Partner-provided or UGC. The corresponding closest match from Youtube Analytics API I believe is using the uploaderType GET https://www.googleapis.com/youtube/analytics/v1/reports?ids=contentOwner%3D%3DXXXXXXXXXXXXXXX&start-date=2013-06-17&end-date=2013-06-21&metrics=views&filters=uploaderType%3D%3Dself&key={YOUR_API_KEY}
But this is at a contentOwner Level rather than at video level.Kindly let me know if I am missing something.