Pete at Bikemp3 has come up with some inserts for the square holes in the cowl to allow standard round foglight installation.
I got a set of the prototypes and they are just what is needed. No more changing the cowl to the older style just to install round fog lights.
Check then out here: http://bikemp3.com/2012-GL1800-Lower-Co ... 12-INS.htm
The pictures show a test fit on my bike.
Fog light inserts for the 2012 GL1800 cowl