Honestly I don't think it'd be that much different. But let's compare just for the fun of it
Shared between years (so your LS harness will already have these): Tach, VSS/Speedometer, Oil Pressure Gauge, SES light
NOT shared, so you'd need to add wires to the cluster for: Engine Temp, Fuel Gauge.
Fuel gauge can be configured in the PCM for PWM output to the gauge, one wire from PCM to gauge and that's done. Engine temp is a little more iffy, you might need to install a temp sensor somewhere as I don't think the PCM has an output for that... 96+ GMT400's have two temp sensors, one at the thermostat housing for the PCM, and one in the driver side head for the gauge.
You would actually lose a few things converting to the early GMT800 cluster, stuff that is controlled by the BCM in those trucks like the high beam indicator and transmission shift indicator readout, possibly other indicators like seat belt, etc etc. I'd stick with the standard GMT400 cluster personally.