The paint on your car is definitely metallic. I believe the other blue offered was single stage blue. All of Nissans metallic paints at the time were two-stage. Pull up the carpet under the hatch and check the factory overspray in that area and in the spare tire well for the original color.
1974 "early" 260Z - L28ET - MS3X full sequential fuel and spark, COP=Ford 4.6 coilpacks w/ Nissan Ignitor, diyautotune chopper wheel - FMIC - T04E .63 A/R - 400cc Injectors (too big!), 14point7 Spartan2 Wideband - C/R 5-speed - Coilovers - Big Brake Kit up front, Porterfield friction all around. Mesa, AZ