Smooth makes it easier to clean.can sand the pan smooth if you like but its not necessary. The finish isn't what keeps it from sticking, the seasoniing is.
Guys casting bullets as well.FYI on used cast iron - I read this years ago as a warning, some fisherman use cast iron to melt lead to make tackle - you can never remove all the lead and it leeches into what you are cooking... just a warning.