If you buy a product from any reseller and there is no public patches or service pack at our Updates section (upper right corner of our webpage), you don´t need it. In most of the cases packages from resellers already have all the patches included.
Usually, we send the installer files to resellers after releasing them on our site first. This is in order to ensure that we fix any potential issues that there might be with the aircraft in the form of a service pack. In most cases, the resellers have installers that include service packs 1 and/or 2 already in them. If there was a need to release a new service pack AFTER the resellers start distributing them, we send the resellers the updated installer, so you can always re-download the installer from the reseller and it will include all necessary service packs and updates.