Checks can be done on the dual mass flywheel to see if it needs replacing. So until the gearbox is removed, you will not know if a new one is needed. Bear in mind though, if it is worn and not replaced, the new clutch may not last long - a colleague had this on a VW 1.9 Polo, new clutch lasted for 5000 miles, then it was found the dual mass flywheel needed replacing.