Our Elky restoration had the same problem. When we were going back together with the car, we couldn't figure out how that skinny trim went on. We even bought the assembly manuals which didn't help. Even if it had clips, there was no room for it between the rubber and the bed trim. We looked at other cars and still couldn't figure it out, Some had it, some didn't. We left it off and it looks and works fine.
I'm trying to remember from my 59, it was about 10 years ago or little more. I seem to think that there are small studs that go through and nut on inside??? Or I could have something way mixed up..... Sent from dumb operator on a smart phone
The windshield did that. Rear window is just captured by rubber channel. Our bed front stainless trim squeezed tightly against that as in photo above, no room for the skinny trim that was with the car.
Mine doesn't have it either. Unless folks are Real experts on 59's ,never know its missing.Have you checked with the El Camino store?