Since I had done a survey and deep dive on the subject of blackout out the visible horn wires on 65 San Jose cars I would start a similar thread for Dearborns since I was in those pictures today. If you have examples of unrestored cars with visible coatings applied to the radiator support and/or the visible section of the horn wires I invite you to post with the cars details so that they can be collected, studied and conclusions drawn from that effort
Below is an example of one example from 5F3645xxx Showing the messy and focused application of a sealer/adhesive over the visible yellow insulated horn wires
Thanks for viewing