Yes it's a Clavinet. I think perhaps Stevie Wonder used a Clavinet model C on that song. Not sure about the sound difference from model D6, but i think the C model was more punchy than the D6.
Anyway. Arturias Clavinet imho is'nt too punchy. But i think it's worth to have in mind that overdub probably was used in superstition, and other instruments blend in.
It also depend on what sound you actually refere to. Which recording?
And off course the playing has be brougt into account. And which EQ has been used? Was a compressor used? A pre-AMP? A AMP? And which Tape recorder and so on.
I think i would start out with the "Default BC" factory preset in Clavinet V. perhaps with a "Slow Keyboard" velocity curve depending on your playing.
As that is, i would not say it's very far from.
