In talking with the seller when I listed their home that was one of my first questions because I knew someone like you would want to know.
They get along very well with their neighbor but they have never heard a pep out of them in the almost 7 years they have lived there.
The adjoining wall is mostly the stairwell, closets and bathrooms.
When these were built code called for 10 or 12 inches of space fully insulated to cancel out any noise.
When is a good time for you to check it out? Let me know and we'll go have a look.