I just realized that WOWOW version of EP 5 and 6 (probably also for the other episodes) used not the 2011 BD master, but the 2015 digital download; as far as I can tell, differences are only in missing Fox logo and new fanfare; color grading of EP 5 and 6 (and 7, too) is the same of the Blu-ray - I checked a lot of frames to confirm that. BUT…

EP 4 (still unsure if the master used is 2015 digital download, but it’s really plausible), at the contrary, DO HAVE a different color grading… not so drastic like the one between previous versions, but it’s there; don’t know if the difference just lie only in brightness and/or contrast and/or gamma; to me, colors also are affected - seems WOWOW has not that pink blanket found on BD.

http://screenshotcomparison.com/comparison/193837

I would like to make a comparison of the Mos Eisley added shots, like the last one in the previous post, but I have not found them.

BD screenshots taken here: http://www.darkrealmfox.com/film_reviews/blu-ray-screencaps-star-wars-episode-4-a-new-hope
WOWOW screenshots taken directly from the broadcast .ts file