Pretty much every spring from 79-04 will fit every single other Mustang. There is just a slight difference in spring rates and lowering distances.
They will fit, they'll only lower about 1 inch although and will not really need cc plates...
There are other advantages of getting cc plates although, such as replacing the stock rubber strut mounts with new spherical bearing mounts (in cc plates), and the car will help hold alignment better under hard cornering...