Also keep in mind that 1968 to 1972 were look-alike years with minor changes to grill and taillights.

That's like asking how many stars are in the sky. Chevrolet didn't keep track of individual production numbers like some other car companies did. All we do know is that there were 349,733 Novas made of those 139,769 were 6 cylinders and 209,964 were V8's (12,309 had the SS option). Out of those totals, it is not known how many were 2 dr or 4 dr.