I can not tell in your picture but you may also need 7561 (2 Wheel Assemblies w/Coupling) If the tabs that hold on the part that Gordon linked are broken then you will.
I was unsure about that too, Ras. Even if the wheel assembly coupling isn't broken I've found that on rolling stock which had the LGB type coupling hook with the little "springs", the new style coupling hook can be a loose fit. I think this is because on the original wheel assemblies the two prongs on the wheel assembly the coupling hook went over had a slot between them running across the truck or carriage and, over time, the prongs came closer together. On the newer wheel assemblies using the current coupling hook, the slot between the prongs runs in line with the wagon or coach the hook assembly fits much tighter. Of course, this not only makes things more expensive, but removing the wheel assemblies without damaging the tongues on the truck/coach chassis is a fiddly business.
(Oh, and if you keep the original wheel assemblies, you have to saw off the cross piece which the LGB type coupling rests against.)
