Yep. And 'series one' doesn't mean it was a 69/70, as S1 cars carried into 71.
If it's the car I'm thinking of (orange), it's a true 71. It's no longer 'original' as it's been painted, and I think it had triple carbs (not original).
The side markers are installed backwards, the C-pillar emblems were removed and filled, the interior is pretty roached, and it's missing some Series One parts.
I'd say (again, if it's the car I am thinking of) it's a very, very nice example of an early Z, but I wouldn't get too worked up over any additional rarity. It's rare as it is, and worthy of being brought back to original condition. Welcome aboard!!