That's no difference. The arms are symmetrical, so you can flip them around or mount the rollers on the back side (because the hole for the fastener goes all the way through). Or mount the left one on the right side. All the same.
What is not the same, is the looks thou. With the rollers behind the arms it doesn't look as good. Imho.
I will have to do that when I mount them to my pinnacle frame. Because otherwise it won't work. (Did I write that already? :facepalm: )