Most definitely YES!
Carbon can physically only treat alcohol up to 55% and trying to run anything stronger than this through carbon is a total waste of time! Having said that, even though it can treat up to 55% we would ALWAYS recommend watering down and treating your alcohol at no higher than 40% for best results.
Note: Many brewers over the years have said they run their spirit straight from the still (at 80-90%) into their filter, and it taste fine so it must work!? This is incorrect, as the carbon is physically unable to do its desired purpose at such a high alcohol strength. Although the carbon may make the alcohol smell better, this is the only thing it has done for that alcohol. Most impurities that you are carbon treating are tasteless, colourless and odourless, therefore just because it looks and smells ok, does not mean it is safe to consume! Always water down your alcohol before carbon filtering.