Actually I don’t really recall.
There is no problem taking your own booz. But you should check first.
I’ve taken two cruises. One was a Mediterranean cruise that went up to Turkey, and the other was Hawaii. Both were very nice.
If you take your own booze it will be confiscated. Your baggage is searched before you get on, and once you get off, for contraband. That includes contraband you bring with you, and that which you purchase there. Booze will just be taken, because that is where the profit margin for the cruise line is. Real drugs will get you a visit from the local DEA.
I took the family on the Carnival Cruise to Mexico back in 07 ... it was a nice cruise. Loved Puerto Vallarta, and Cabo. Not impressed at all w Aculpolco. Surprised this happened in PV.