Here is the cover shot of the car. Note that the car is identified as an "SS396".

Without posting the entire article, the author states that of the 5,272 L-78 Novas built in 1969, a "handful" were not.
He does state that there are no records as to how many were built as non-SS cars. There is also no mention of the history of this particular car, so no ducumentation is mentioned. (This is the magazine's way of generating controversy, which is always good for business).

Carry on.