I too want to find out if the unit is interchangeable as well. I was quite disappointed in the low quality optics considering the overall cost of the option. I too have a Gopro which we use more for wearing and other remote mounts. However like rdpthree mention, I too would rather utilize the built in system but at a higher quality. Looking at the links you provided, I do see the camera is slightly different inshape. If it doesnt just slip into the existing bracket, worst case, you can always order the new 2012 pylon parts to make it work.
BTW... welcome to TT.. lots of good information and people on this forum.
Current: 2009 X-Star, Indmar 6L, 400hp, ZFT3 tower. c/w 1/9 scale R/C PWT X-Star
2009 Moomba LSV
2009 Moomba Outback V
2008 Monterey FS180
Pelican 4 set paddle boat
plastic tug boat when I was 4