All I have are verbal descriptions. Here are two:
“The front structure assembly was built first. It was created by assembling, in the fixture nicknamed the “Merry-Go-Round”, the dash panel (also sometimes referred to as cowl or firewall), the left and right inner engine compartment apron panel assemblies, the radiator support, and the outer side frame members. These pieces were spot welded into one single assembly.”
Mustang Genesis – Bob Fria (pg. 150)
“The Mustang’s engine box, known simply as the “front end assembly” at Ford in those days, was assembled in a huge jig that was part of the “Merry-Go-Round” where several front end assemblies were assembled and welded together by automatic and human welders. The Merry-Go-Round concept originated when 1962 Fairlane production began at Dearborn in 1961.”
Mustang Production Guide Vol. 1 – Jim Smart & Jim Haskell (pg. 7)