I"ve seen pie weights bolted to the front axle before. If, as it appears, these are 45 lb. "heavy" AG weights, the total weight on the axle is actually just a bit less than a full set of heavy front wheel weights.
The tractor does not look to be a 6x0. The front spindles/wheels and drawbar bracket have 2000 LCG written all over them. Looks like a hybrid.