Link to a web page where you can watch many of the equipments Jean-Michel and his staff has used all these years and (sometimes) on wich albums.
http://www.jarrography.free.fr/jarre_studio.php
Some sounds on the Magnetic Fields album were ie. created with Fairlight CMI-I, Oberheim OB-X and Moog Liberation.
All you can do is trying to find out on wich "consumable" synths you best can duplicate those old dragons.
What sound on wich synths that are the closest or easiest to produce seems to be pretty much a personal taste.
I'm not that much "into this" but for Chronologie Roland JD8000 seems to be a popular tool and Oxygene 7-13 was almost
like a commersial for Nord Lead synths, even if other gear ofcourse were in use.