Scoured through 4 pages of search results and didn't find an answer. I am preparing to install factory seat belts (front & jump) into my '69 and '71. The hardware in both trucks is not original, and while I'm not looking for perfect OE hardware, I'd like to get the details correct. I understand the threads for seat belt mounting are 7/16" fine threads. What I cannot find any info on, is if the proper seat belt mounting hardware requires stepped washers that allow the terminating end of the belt to rotate after the bolt is tight. The theory here would be that you can tighten the bolt and stepped washer, and the washer allows the belt to still rotate freely around the bolt in accordance to the direction of force applied to the belt. Here is a photo from one thread that shows the stepped washer, but there was zero input on what the actual correct hardware is. Again, mounting lap belts up front and jump belts in back.