Can you log into your old account? I don't know if that would get you in trouble for Multi Accounts, but if you can post on that account you aren't banned.
I have an account from 2018 @Zenarith but I lost my email and password so I created a new account.
I did see Guest before and I assumed it was before the Forums required you to register.
I think Banned would be Banned...
Maybe during the Pruning they thought you weren't coming back but didn't want to delete your Posts on the Forum.