Is a Lewis dot diagram the same as a Lewis structure?

Yes. Though in practice they are a little different.

A Lewis dot diagram is a convenient way of showing where all of the electrons in a compound are. Because it involves showing all of the electrons as dots, it's usually reserved for showing the on atoms or for teaching students where the electrons in covalent molecules are.

Lewis structures, on the other hand, are the version of these diagrams that involves lines and dots and such - these are used for both big and small molecules. The concept is the same as for a Lewis dot diagram, but it's a whole lot easier to draw because a lot of the dots are replaced with lines.

Here is a video which discusses how to draw Lewis structures for atoms showing their number of valence electrons. Video from: Noel Pauller

OK.