Something else I just remembered is that many tv airings of Godfather 3 have a different opening which is a montage of scenes from GF1 and 2 to recap the story, but shown as flashbacks as Michael sits and ponders it all at the Lake Tahoe estate (the same shot we see of him at the end of the theatrical GF2). However it looks like they used extra unused GF2 footage of him from that scene for this alternate opening between the flashback moments.
Something else I just remembered is that many tv airings of Godfather 3 have a different opening which is a montage of scenes from GF1 and 2 to recap the story, but shown as flashbacks as Michael sits and ponders it all at the Lake Tahoe estate (the same shot we see of him at the end of the theatrical GF2). However it looks like they used extra unused GF2 footage of him from that scene for this alternate opening between the flashback moments.