Retainer is inserted into the locator (part # 604421) the same way the plastic ones are. With the retainer inserted into the locator, the bolt is installed so that its threads pass all the way through the retainer.
The retainer will remain loosewithin the assembly, but does not rattle due to its outer diameter and the fact that the retainer is made from aluminum.
When the bolt is unscrewed from the locator bracket (part # 604424), the threads of the bolt make contact with the retainer,and prevents the bolt from being removed.
The over-sized minor diameter of the retainer thread and the cylindrical outer surface of the retainer prevent the threads of the bolt from "starting" (the retainer will just spin) and is thereby captured. In this position, the roof may be removed from the vehicle, and stored in the trunk, with the bolts attached. (No need to find a place to store them.) When re-installing the roof, the bolts are simply tightened down into the locator bracket as normal. If the retainer eve