Dried ghost peppers as well as other dried Jalapeno pepper do get hotter the drier and older they get.
Although fresh ghost peppers and other Jalapeno peppers are pretty hot when fresh the ghost peppers and other Jalapeno peppers go through a chemical process that causes the ghost peppers and other Jalapeno Peppers to get hotter.
Every time I've ate dried hot peppers including the ghost pepper they were hotter than they were when fresh.
Some people will hang the peppers up to allow them to dry out and become much hotter to use in more spicy and hotter foods.
I knew a Mexican lady that was a good cook and she would hang Jalapeno peppers out on her porch in the sun to allow them to get drier and hotter to use in her recipes.
The longer the Jalapeno peppers hung out to dry the hotter they got.