As a preview, and in honor of President Monson's funeral today, I'm sharing a still frame from the video that shows young Elder Monson sitting next to young Elder Hinckley. They are in the lower left corner, next to the silhouettes of our BYU faculty who are watching General Conference with us.
President Romney is at the podium, with President Kimball to his right and President Benson to his left behind him.
President Hunter was present, but not visible from this perspective.
BTW, sitting next to President Benson behind Pres. Romney are Mark E. Petersen, Delbert L. Stapely, and LeGrand Richards.
In front of them you can see Boyd K. Packer and just a glimpse of Marvin J. Ashton.
For context, here are the members of the First Presidency and Quorum of the Twelve at the time. President Monson outlived all the others.
Spencer W. Kimball, President
Nathan Eldon Tanner, 1st Counselor
Marion G. Romney, 2nd Counselor
Quorum of the Twelve
Ezra Taft Benson
Mark E. Petersen
Delbert L. Stapley
Hugh B. Brown
Howard W. Hunter
Gordon B. Hinckley
Thomas S. Monson
Boyd K. Packer
Marvin J. Ashton
Bruce R. McConkie
L. Tom Perry