my 68 fast back does not have a trunk light, i want to install one...
is there a hot wire dedicated to this already in the car, or do i have to run one from the front?

You could T into the small filament taillight circuit (your running lights) so the trunk light would be hot anytime the park lights or headlights are on otherwise if you wanted the trunk light to be available anytime whether the running lights are on or not yes you'd have to run a wire up front & the closest point that is hot all the time would be the dome light or rear pillar lights if the car has them & the pink wire is the hot wire & on all the time

here is a wiring diagram