When I see the low mileage; heck sometimes almost any mileage on the odometer, I automatically add 100,000.
That's is almost assumed by anyone who knows these cars.
So often the clusters are swapped or rebuilt, powertrain rebuilt, or this or that - that you almost have to ignore the odometer.
If I were buying a 1987 GrandAm with 132,000, I'd be a little more concerned.
About 2 years ago - I saw my old 1987 GN that the ex-wife / bloodsucker sold for pennies on the dollar in 1995 after our divorce - advertised for sale, and they claimed it had less miles on it then when I owned it.
Not sure exactly how that works.
But I would hazard to say the odometer rolled over.
So, those odometers don't hardly mean much.