Good question, answer is no it happens before cure. The density is first determined by the genetics, second the grow conditions for some strains higher temps mean loser fluffier buds. Also in consistant temps can also cause looser buds I have been told. And last but not least timing when you harvest. I know everyone wants their autos done in under 80 days but sometimes that doesn't happen. IMO the last 20% of weight they pack on in there last 2 weeks is the density or "hardness" your looking for. So 1: genetics 2: lower temps under 80F if possible 3: Make sure she's fully mature when you harvest!