Your car was originally Silver Jade (code 4) with the black out hood treatment (code 5), hence "45" as your color code.
Here's a pic of a Silver Jade 69 Mach 1 with the black out hood treatment, this is EXACTLY what your car looked like originally, http://www.svs.com/users/zim/mustang/images/69-4.jpg
It's a little cloudy in that pic but it is a metallic paint.
(personally I love that color, one of my favorites in 69. A very nice shade of green that really "pops" in the sunlight)
EDIT: I should mention that Silver Jade is a different shade of metallic green than Lime Gold (code I) that everyone has a love/hate relationship with. Lime Gold is the color some people call 'puke green' or 'metallic pea'.
1968 Mustang coupe, Acapulco Blue, 289 2v, C-4, Power Steering.
Hopefully a 1969 convertible or Sportsroof (non Mach or Boss) for next Mustang project
Trying to find my father's 1973 Mustang Grande he bought brand new. 3F04F126773 last known registration and title was in New Jersey, 1982.