Production numbers

I was wondering if anyone can tell me where to find production numbers of cars built exactly like my 1972 Dart Swinger "Special" the fender tag says it came with an engine that was not available that model year. I know it is rare, I just dont know if that makes it valuable. I am trying to determine how I should put it back together, stock or modernized
vin says it came with a 318, fender tag and build sheet both say it came with the 230 horsepower 318 which was discontinued the year before. it's hemi orange with a 3 speed on the floor with chrome road wheels, it's essentially a 340 Dart without the 340