The RA60 disc has a very slim hat. You need an adapter plate to bolt them up to sprinter hubs. Don't know about the calipers - I have Volvo 4spots on my setup (that uses AE86 struts and RA60 discs).
Once you undo the 4 bolts holding the disc to the hub they should come apart. It might need some "persuasion" if it is all a bit rusty...