I bought the optional front rack for my Radmini from the Radpowerbikes website.
It seems the three top and one bottom accessory mounting points on the rack are 5mm. The included hardware is 6mm. Has anyone seen this problem?
I think the included bolts were for the rack mount to the frames. The frame already had 4 bolts screwed into it though.
It has been a while since I've installed one but yes, you use the bolts that are already on the frame. The others may have been included accidentally - or to screw into the top of the rack in case you're not going to purchase their basket.