This is a beautiful first-pressing copy on the orange Minit label (plays normally, at 45 rpm; collector nerd alert: a rare mis-pressing plays at 33 rpm). Yes, "Mother-in-Law" deserves to be on Dave Marsh's list of the 1,001 greatest singles, and it's one of the late, great New Orleans musical genius
Allen Toussaint's biggest hits as a songwriter (he produced it as well, but it's not credited on the record). But have a listen to the B side... over time, I gave it 5 stars in my iTunes library, where "Mother-in-Law", I see, has only 4 stars. It's a catchy song that swings more than "Mother" and veers toward the sort of proto-Soul Lloyd Price was doing at the time.* Note: This beautiful copy has a Near Mint labels. Despite a few notable scuffs on the vinyl, the audio is very close to Mint.
* A 5-star rating in my iTunes library translates to a 2-star recommendation from us (yes, my wife gets to weigh in, too. :-) on Classic 45s; a 4-star, to a 1-star. Of course, our recommendations only show on a record's detailed page or in a search list for 45s that aren't already on one of the other lists we maintain  Dave Marsh, Kev Roberts, and Rolling Stone.