From 8+ Years Ago:
If you're interested, this was discussed in a 2008 thread: Wondering about those holes.
It may have been discussed since, but that's the thread where I encountered the topic.
If you want to get something much classier looking (and, yes, more expensive) than Suzuki's shiny metal bolts and sleeves, I can recommend Triumph track-stand bobbins. Here's an old pic of my former 2007 Exec, but I did the same thing on the 2008 I acquired last year:
Note that the unseen bolt that comes with these is an M6, and with the Triumph part # A9648003 it must be shortened by about 1/4" (or replaced with a 35mm M6 bolt). This information is from this pic and caption of my gallery -- http://www.billanddot.com/burgman/#47
-- where I also note some suppliers of the product.
Further note that your average, garden-variety, bobbin won't
work in those embedded nuts. This Triumph model works because it has that taper at the top, whereas most bobbins have a straight outer body, which precludes their fitting in the rail (at least in front).
When doing multi-day, one-up, trips, I travel with an Aerostitch Medium Motofizz bag that I acquired a decade or so ago: http://www.aerostich.com/medium-moto...-seat-bag.html
. We can discuss the merits of different travel bags all day long, but my point here is that the Motofizz has loops embedded in some of the adjustable straps, and the bobbins are perfect for using those loops to secure the bag in place atop the rear seat.
[Edit: one last thing I forgot ... No, I wouldn't try to lift the bike with anything that screwed into those nuts, but I've found them surprisingly rugged. I would not hesitate to lash anything you're carrying onto them.]