All painted fairing pieces are fully interchangeable between
all C10 years.
There are very minor differences particularly in 1986 lowers, however it does not affect interchangeability.
Because the dash changed in 1993 the fairing inners (black parts) changed and are incompatible pre and post '93.
Early '86 upper inners (black parts) has an extra bolt hole, this does not affect interchangeability with other pre'93 inners.
There are two different belly pans (not sure which year is which) however all are fully interchangeable.
There are two different headlights, (Yankee lights have an extra globe) they are interchangeable.
Dunno why they had to keep changing things...