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If a grammar has the same variable multiple times, is it the same as adding a $\mid$ between them? For example, is
$$\begin{align*}S &\to bB \\ S &\to \varepsilon \\ B &\to cB \\ B &\to \varepsilon \end{align*}$$
equal to the following?
$$\begin{align*}S &\to bB \mid \varepsilon \\ B &\to cB \mid \varepsilon \\ \end{align*}$$
Yes. (you are right, the "$\mid$" sign is a classical notation for the alternative rules for a variable.)
