Never tried the decon Dunks but my decon Isle Blazers fit a bit bigger due to lack of padding, potentially could do half size down as I have to choke them a lil bit but then I wouldnt have room for my toes. I assume Dunks would be the same if not more since they are even more padded.
I'd say if you wear your shoes snug already then stay TTS, if you already wear a roomier shoe they'll likely be a bit too loose.