Great question. The answer is no, you do not need to deactivate any tweets you created within your Content Pipeline that may be in violation of Twitter's posting rules.
However, Lately has set new parameters in our content creation tools to protect your Twitter account(s). Any Twitter posts you already scheduled that are in violation of Twitter's new rules will show up with an error. It they're not edited prior to the scheduled posting time, they won't be published and will end up in the "Failed" status bucket in your Content Pipeline. From the "Failed" status bucket, you will have the opportunity to edit the post, and choose a new time to schedule. If you edit the posts before their scheduled posting time, they will go out on time.