Looking through the Continental website and the vehicles listed against each belt here is what I have found:
* 4PK592 ELAST - suitable for R1200GS (and ADV) 2004 - 2012
* 4PK582 - not suitable (they only list Volvo's as being compatible)
* 4PK611 - suitable for R1150 GS/RS/RT & R1100 GS/R/RS
* 4PK611 ELAST - R1200 GS/GSA/S (2004 - 2012) & R1150 GS/GSA/RT/RS (2002 - 2005)
Here is the link so you can run your own search:
https://www.continental-engineparts...IC-Product-Information-Center-1/?lg=en&artnr=