If I understand what you are asking, you want to find a post that would be in the 300+ range in the past, correct? It would not be easy with your number of posts but if you knew about when it was posted you could list all of your posts and look for the specific date. Not easy. Or if you knew the subject of the post or a key word or two, you could do a search entering the information as a search point. Still not the best way, perhaps, but easier than reading each and every one of your posts.