Not long ago I purchased (and have since sold) a nice 1200 Standard with the Samsonite bags (which I still have) but apparently the mounting hardware was intended for the 1100 since short homemade adapters were used to lengthen the mounting tabs (under the shocks if I recall properly). I am thinking of installing them on an 1100 that I plan to restore in the near future.
I too have seen them on Craigs list for around $200.
Bikes at present:
80 GL1100 Interstate: Now a Cafe Racer called DRAGON WING.
81 GL1100 collecting dust with about 300,000 miles, known as BLACK BEAUTY
2008 (I think) GL1800 Nice bike but as exciting as the family sedan!
76 GL1100 yes, 1100 with 1000 heads and cams, being customized
A fleet of parts bikes awaiting resuscitation or customization or abandonment