Ninety nine percent of the time once you have gotten ungated in a category or brand, you will not need to sell the product in order to stay ungated. Ungating is usually permanent unless seller central coincidentally requires re-approval (this could be because there was a mistake on their end) or Amazon has a new list of requirements in order to sell the product.
How do I stay ungated?
Is ungating temporary?
Do I need to get reapproved to sell a brand/category?