Mike,
Did you arrive at that weight by actually weighing the tractor? It would be interesting to see just how accurate the specs are. Specs say:
Tractor with Ag tires 3042
KL130 with bucket 770
2475 backhoe without bucket 1069 (shipping weight)
2375 backhoe without bucket 855 (shipping weight)
Using the 2475 and let's say the shipping weight is a little higher than the actual backhoe, but is offset by the weight of a bucket (a wash). That adds up to 4881 lbs. R4 tires would add a little. Not sure if fluids included in tractor weight. The difference (assuming the same equipment) is more than 750 lbs, and that's quite a bit.