You have the same set I have (the Givi brand, not the Kawasaki brand). I just installed it all today. You need to get PLX447KIT along with PLX447. PLX447KIT includes two small brackets that connect those mystery flanges near the grab handles to the frame underneath the seat. I believe it also included spacers that fit between PLX447 and where it bolts to where the round reflectors used to be. I can't remember which kit those spacers came with, but if you noticed that there was a big gap when bolting the bracket to the bike at that spot, you need those spacers. They're not just washers. They're about 1/2 thick.
Anyway, if you had ordered FZ447, those mystery flanges would bolt to that. But without FZ447, you need the small brackets in PLX447KIT to take it's place and fill in the gaps.
The Kawasaki brand brackets (available in US only I believe) are completely different because they're designed to prevent you from mounting the tailbag as well. Whereas the Givi PLX447 is designed to allow you to mount a tailbag with the saddlebags, which Kawasaki (or the US DOT) doesn't like for some reason.