I am looking at the same plate mount for my SG. I have not seen any other bikes with this mount. Only pic's I see are on the Kuryakyn and parts store websites.
I don't believe it will fit. I bought one for a 2010 RK and the holes were too wide on the fender. I contacted Kury... and they said that they did not have one for the newer touring bikes. At this point, I am unable to find one that works. I need to put the plate below the light and am having trouble.
I contacted Kuryakyn about this license plate holder for my 2010 SG, here's their reply:
Unfortunately item number 3163 will not fit the 2010 FLHX due to the bolt spacing is different on the 2010 models. If you have any further questions, please feel free to contact us.