Got the "kits"
From OODM. Replaced two of them.
Different from "stock".... The original appeared to have Teflon or nylon on the long shouldered female part. The new is clean. No coatings. It looks like a "blind" nut but of course it is not. It is a flat head with long shoulder.
The holes in ends of links are stretched a bit due to use and age.
There is a "wave" washer in the KIt that goes between the links an over the shouldered nut. It really snugs up the links making step more stable feeling and easier to deploy.
YMMV... This is expensive solution, but now I know how to make my own. I will make up my own KIt. Soon.
Peace and Blessings..