You are correct. There is no difference. The two main bean types are robusta and arabica. You can make espresso with anything. Now, bags branded as espresso are generally roasted a bit darker, as espresso using light roasts is less common traditionally, but you can still make espresso with light roasts.
There are two primary varieties of beans, arabica beans and robusta. An expresso bean (arabica) is generally darker (roasted longer) with more visible oil.
People didn't like my answer, so maybe this site would better explain:
Nevertheless, when you compare espresso beans vs. regular coffee beans, you’ll notice the former is always dark roasted and oily. This is not to say that regular coffee beans cannot be dark and oily. However, they can feature other characteristics as well, while for espresso beans, these qualities are non-negotiable.