No.
Your authorization serial number is emailed to you when you purchase, so it will always be available to you in your email account.
Furthermore, all details, including permanent download links to your purchased plugins, are always available to you from your Surreal Machines online user account. If you need to reinstall any Dub Machines plugin, simply visit your account, download your linked files and use your serial.
If you purchased from Plugin Boutique your serials and downloads are similarly available at your account with them.
If you ever have any authorization problems that cannot be solved via your account, contact support@surrealmachines.com and we will get you a new link or serial as quickly as possible.