RPO GT4 shows it's a 3:73. I know that's for the rear, but the front has never been changed. The axle shafts in the original diff were smaller in diameter and not interchangeable. The exterior was the same though. Yes It is definitely a 10 bolt and 3:73.
Have had my 98 Z71 for a long time and love it. Parked it a while back because life got in the way of fun. The rear end was always loud, and I purchased another from a friend. Went in perfectly, sounds much better, but noticed an odd vibration. Turns out the drivers side axle is slightly bent...