Can a 1996 chevy silverado differential have 10 bolt pattern as original?

[valkyrie1520]

I have a 1996 Chevy silverado 5.7l V8 I have been trying to figure out if the rear end has been changed out. The first give away was speedometer registers 80 mph while gps shows 72 mph.
In trying to figure out I found a 10 bolt pattern differential and orginal rpo code shows GU6 : AXLE REAR, 3.42 RATIO