Correct, but RSS also performs secondary checks.
Agreed, but as above, the password is the only protection. If you have the password, you can request any information from the panel.
Once RSS gets authenticated with the password, it then checks the other ID's for matches. It does this by requesting the panel values and then checking that they match the values stored in the site.
What is the error message that RSS gives ? If the password is correct, then it will complain that the site ID or something else does not match. In the newly created site on the new system, you need to add these values in. There's no other seeding of the RSS password.