Pink calloused skin is normal, and you don't want to be applying anything unnecessarily as this can sometimes aggravate the skin and result in sore hocks setting in when there was no problem previously. You also don't want to be applying any bandaging when it's not necessary, and when you don't have experience doing it and/or a vet hasn't shown you the proper application, as bandaging applied incorrectly can restrict blood flow to the foot and could result in a serious injury occurring because of this.
To me your rabbits hocks look to be normal pink skin, but it can be difficult to tell for sure just from a photo. With sore hocks you are looking for skin that looks inflamed and dark pink or red. It may also look puffy. Open wounds would also indicate sore hocks. If they are just starting to look sore, evaluate the flooring and determine if any changes need to be made. Also keep the nails regularly trimmed as long nails will alter how a rabbit distributes it's weight on it's feet. Long nails will cause them to shift their weight back to their hocks. Flooring changes and keeping nails trimmed is usually enough to correct the beginning of sore hocks when there are no other issues contributing like old age and arthritis.
If in doubt it's always best to consult a knowledgeable rabbit vet.
https://rabbit.org/vet-listings/