An asset's internal ID is not related to the scanning server that scanned the machine, so no: changing scanning servers won't cause duplication.
If you will just be moving the Lansweeper service, the steps are the following:
• Delete or disable the Lansweeper service on your current server. Right-click on the service in services.msc, select Properties and choose the appropriate option from the Startup Type dropdown.
• Run the script below in the Lansweeper web console under Configuration\Scanning Setup\Database Scripts, replacing NewServer with the NetBIOS name of your new scanning server and OldServer with the NetBIOS name of your old scanning server.
update tsysasservers set servername = 'NewServer' where servername = 'OldServer'
GO
update tblassets set scanserver = 'NewServer' where scanserver = 'OldServer'
GO
• Run the Lansweeper installer on your new server, choose New Installation\Advanced Install, select
ONLY the Lansweeper service for installation and also check "use an existing SQL Server".
DO NOT check the checkbox in front of “Lansweeper Database”, or you’ll be overwriting your existing database.
• Point the installer to your existing database when prompted. You can find the necessary database connection details in Program Files (x86)\Lansweeper\Service\Lansweeperservice.exe.config on your old scanning server.
• If necessary, update the Action Path listed in the Lansweeper web console under Configuration\Website Management\Asset Pages. Your Action Path indicates where the Lansweeper web console will try to locate your custom action executables.