Depends on 1) if the leather is still available, 2) if the pattern is available and 3) if you have a dealer willing to order them for you.

I stopped doing this several years ago for clients because they were never happy with the results in over 90% of instances. Even if the leather is available it is going to be nowhere close to a color match, it will make your sofa look like a jigsaw puzzle. People often demanded a refund and got very upset when told "No" because it was custom made for you.

The Highland sofa was dropped many years ago. If your casings are shot, that also means your cores are done as well. Do yourself a favor and just buy a new sofa, things get used up and new casings are not inexpensive. Six casings and Six Cores will be $ 1,500 to $ 2,000 and you may not like the result.