I don't know if this will help in your situation, but I am in the process of dealing with similar work.
I had detachable hardware on my Super Glide from when I used a detachable sisst bar for the times the wife rode with me. She had since bought her own scooter and I hated the sissy bar.
I am putting a 180 tire on and want to get the signals off the struts. I have purchased the HD Bullet Style Turn Signal Bar (68615-04) for touring bikes and as comes stock on the Street Glides. The detachable hardware I removed has slugs for both sides of the rear of the struts. The hardware also included different strut brackets for the underside of the fenders. These brackets are threaded at both holes so bolts can be installed from the outside of the struts to the inside. The slugs are chrome and have one hole in them This hole will allow me to use a chrome button head bolt (3/8" x 1") to secure the rear of the strut while the rest of the slug covers the second hole at the rear.
Hope this explains it correctly and offers you some ideas and help.
John