4k77 is missing one frame at the end of reel 5. The only available source was the BD so it was not used. If the 35mm prints were complete then it would have been used in 4k77 for historical accuracy and preservation. The BD frame should have been used anyway IMHO.
In hindsight, it absolutely would have been better if that one missing frame was reinserted into 4K77. That way, it would be clearer what the objective of the 4KXX project is (preserve the entire trilogy, GOUT-standards be damned) and if nothing else we could have had these arguments ages ago!