Yes, all of your data (domains, users, emails) and program settings will be intact when uninstalling/reinstalling. Only the program files are affected with a uninstall.

 

However, to be on the safe side I would uninstall prior to reinstalling even if they are the same minor version. The reason being is that there are files that need to be registered in the Registry and added to the GlobalAssembly for .NET. Multiple instances of these could potentially cause unintended issues.