Since
@gawithhoggarth didn't answer the question, I will. I recently smoked both Samuel Gawith Brown No 4 and Gawith Hogarth Brown Irish X and can say with certainty that they are not the same at the time these were produced (both were purchased and jarred in 2017). I like them both, but I find Brown Irish X to be richer in flavor and a bit stronger. I obviously can't speak to current production.