You say pannier RACK thingy, I assume from that you are talking about the rear rack and not the pannier-frames?
The Adventure panniers fit fine (I have them on my own 03 1150 and recomend them) but I believe the rear rack (for the top-box) is a different matter as the seat is shorter, the rack longer and consequently the rack sits further forward than the normal GS item.
I stand to be corrected, but I guess that it you did somehow manage to make it fit with the standard seat then it would be a lot further back then normal. To mount it in the correct position would mean changing over to the Adventure seat.
NO, not without switching all the harware over between the two bikes as well - stick with your mangled rack, the Adv rack won't take the frying pan or basket
Now to re-clarify, if we're talking about the ADV rack then my answer applies, if we're talking about the top box then Mick's pictures answer this for you.