I don't think it's something you need to over think either. If you have time and want to clean up grammar and such, do it. If you want to leave it as-is as a testament, that's great, too. There is no right or wrong here, just what works for you. I've found it fascinating to go back and see just how much my style has changed. If I decided to clean it up, I wouldn't be able to look back and see how many times I used 'that' in my other stories. The only thing I did clean up, with a simple search and replace and no regrets, I might add, is the sheer volume of exclamation points. It's embarrassing really. I don't want to talk about it.