Okay, when I am running solo and the rare occasion I do not have a fender bib on, which is next to never, I keep the screw in place so I do not lose it.
The CVO SG have a chrome cap that snaps into the fender nut for a cleaner/finished look. As far a what to do with the screw itself, just get a nut and screw it to the passenger pad for safe keeping when you are just going solo. Now if you loose the passenger seat pad, you loose the screw too.
I use a Brukus fender security screw with a gloss black cap on it. Protects everything from crud and looks better than an empty hole or the stock bolt.