Hola a ver si te sirve esto,sacado del Ibanez Forum,aunque es en inglés.
Super 58: Alnico 3 magnet, deep, smooth, round, jazzy-bluesy, PAF like tone. The absolute best humbucker i´ve encountered, have them in both the vintage (original in an ´82 ar500) and new (fitted to a ´08 as93) version, they never get shrill or harsh, touch sensitive and dynamic and.... Just lovely.
Custom 58: Alnico 5 magnet (today), early version had ceramic magnet, clear, focused, more treble, rock´n´roll tone, i have them in an af125 and i was thinking of change them for super 58s but they turned out to be very nice on their own and give me an alternative to the super 58 tone. They can give a shrill tone (compared to the super 58, maybe i have the ceramic version, i´m not sure) at some settings, and need some dialing to find the smoothness i want, but i didn´t change them and maybe that tell something.
Aquí tienes el enlace.
Y los catálogos de Ibanez de la época.
En cualquier caso,lo mejor sería que midieses con un multimetro los valores.
"Cuando todos piensan igual, ninguno está pensando". Walter Lippmann