confused as to if we are required to go thru customs

First of all, you are not asking the correct question.

Immigration (passport control) is different than customs. Customs is if you are importing goods into the country. In Europe, customs is as easy as walking through the green exit door (if you have nothing to declare) after you pick up your bags.

I think you really want to know if you are going to go through passport control in Munich or if you will be able to simply transit the airport in a secure area without needing to go through passport control.

When you return to the US, you will declare how much you spent on what you bought in other countries. If over $800, you pay a duty.That is customs. In Europe, you walk through tne “Nothing to Declare” door after going through immigration, passport control.

Is this trip and flight on the same ticket? If this is one ticket purchased and the airlines do code share they will send your bags on through and you will not pick them up until you arrive in Dublin. If you purchased two separate tickets (SF to Munich, one ticket, Munich to Dublin a second ticket) then you will have to exit the flight, go through passport control and then pick up your bags at the baggage area. You will then have to take your bags to the AerLingus baggage check and check your bags again. You then will have to go through the security check line as if you were just arriving at the airport. I had to do this while flying from Indy to Dublin on two tickets, one to Philly and the second on to Dublin via Heathrow. At Philly we had to get our bags at the baggage carousel and walk with the bags to the second airline check in area. We were flying on American and British Airways but had to purchase our tickets as two separate legs to use our points. Even though American and BA code share they would not transfer our bags because it was two separate tickets. If we could have used points for the entire flight out, one ticket, the bags would have gone the entire way and we would not have had to pick them up until Dublin. We had no customs issues because we had not yet left the US. I am responding because I think you will be really close on time after you go through passport control and locate your bags. I cant answer the part of your question about taking your bags through customs...only about the two ticket issue. Hope it works out.

Sorry i forgot to mention, yes this was booked as one ticket (using United Mileage ) not multiple tickets. Interesting the Lufthansa person said to me, you should have booked a Lufthansa flight all the way thru, well i wold have if it was an option.

That is funny, Lufthansa or any airline would probably train their employees to encourage people to book solely with their airline, even after the fact.

Being all on one ticket should mean you can check your bags straight through to Dublin. However, is there any chance you can pack light enough to have carry-ons only? I especially think of this in light of the fact that some friends just returned from Europe where they had connecting flights like yours, and the airlines lost their luggage (for a day or two) both going to Europe and coming home!

Not having any checked baggage would reduce your stress level considerably, even if you end up mailing stuff home to yourself at the end of the trip. Say you pack w/o any warm sweaters, then buy a sweater or two during your trip and mail it home. That's one way to save space in your luggage.