Are propaganda and rhetoric the same thing?

No. Rhetoric can be used to advance Propaganda, but they are not the same thing.

Rhetoric is the art of discourse, a process that aims to improve the facility of speakers or writers who attempt to inform, persuade, or motivate particular audiences in specific situations.

Propaganda is a specific communication that is aimed at influencing the attitude of a community toward some cause or position by presenting only one side of an argument. Communications are often denigrated as Propaganda when they not only present only one side of an argument, but do so using false or misleading information.