Just bought a 2015 Spyder RT Limited it has these armrest on it

It is attached with three bolts, I am assuming that there is a nut on the other end. Apparently, one of the nuts have come off and the bottom of the armrest swings out. Can someone advise me on how to get to the back side of the mounts?
I am guessing the whole speaker mount will have to come off.....

It is attached with three bolts, I am assuming that there is a nut on the other end. Apparently, one of the nuts have come off and the bottom of the armrest swings out. Can someone advise me on how to get to the back side of the mounts?
I am guessing the whole speaker mount will have to come off.....