First batch (all-white, no punchcard reader, lights running upwards): 1972
Second batch (the model used by Jarre and Göttsching): 1973-74
Third batch (the unit pictured at synthmaster.de): 1975-1977
Congratulations on this rarity.
"Like the light from distant stars, Stephen Parsick's music has existed for some time, but is only now reaching us on Earth." -- Chuck van Zyl / Star´s End