Early cars have a single group of bullet for both sets of front lights which reaches to the middle of the car. The light units have long tails to reach these, but it seems that current stock only has short tails to reach the later harness connections by the headlights. Note the single horn tail, if a second horn was fitted a sub-harness daisy chained from one to the other.
Later harness have the bullet clusters by the headlights, which should be relatively easy to reach between the radiator and the slam panel on cars other than V8s and 4-cylinder from 77 and later. For those the mesh grill has to be removed to reach back under the slam panel and access is still restricted.