I believe nuking deletes all posts and bans the user - so their status is also reset to brand new.
I don't think SMF actually stores edits.
Thanks TradeFortress and BadBear for the confirmation.
When I first registered on this forum (way back in May) I initially started showing my edits or adding notes like "Edit: spelling". I stopped doing this as it didn't seem like many people did that here. I believe that SMF has a function to indicate if and when a post is edited which can sometimes be useful and encourage people to describe their edits. I have also noticed in some threads with more heated discussions, that users quote other peoples posts without adding any comments, I am guessing that this is to make a record of the original post in case it is edited later.