Nativeexpat: An Apostille is essentially a verification of a signature, but it is different than a notary in that it is the verification of an official public signature by the designated state (literally state not federal government in the US, while I assume federal government here) authority authorized for apostilles. For example, we were married in Washington, DC. Our marriage license is signed by the Deputy Clerk of the Marriage Bureau of the Superior Court of Washington DC. The Apostille attached to it is signed by the Secretary of the District of Columbia (the authority in Washington DC that signs all Apostilles for the District of Columbia). It says

This public document has been signed by XXXXXXXX
acting in the capacity of Deputy Clerk, Marriage Bureau
bears the seal/stamp of Superior Court of the District of Columbia

This is followed by the signature/stamp/date/number of the Secretary of the District.

You can get an apostille on a notarized document, as the apostille certifies that the notary signature is official, not your signature.

I have not idea whether desertrose's advice is right or wrong. Sounds plausible.