Gas over comes back out when filling up

I attached a TSB that addresses this. You are on the right path but I don't think the filler neck itself is clogged (it could be but is less likely) but rather a vent line that allows the air out that gets pushed up out of the tank as fuel goes in.

Take a look at the TSB and let me know if you have questions. Keep in mind if you are not comfortable making the alteration that they layout to prevent this, then I would take to a shop and have it performed because it does have you cutting on the fuel filter housing. However, you may get away with just blowing out the vent lines that it is telling you if you want to try that first.