Why doesn't the brake disk on my truck match what ANY of the auto parts store say it should be?

I've gone to 4 different auto parts stores in town and each on says the brake disk for my '97 Dodge Dakota 3.9L should be one way (pretty simple and mounts using the tires bolts) but the one I have on my truck is different (has a huge hex nut in the center that holds it on)?Why doesn't the brake disk on my truck match what ANY of the auto parts store say it should be?
to get the right part for it you have to give them the manufacturer date of it,you may have a split year model truck and they used two different systems on some of them,take the date off the door post and always use that when buying parts for that truck,this way you,ll always come back with the right parts for it,you got the early style on that one,the newer ones just come of when you remove the wheel and the caliper and bracket on it,good luck.Why doesn't the brake disk on my truck match what ANY of the auto parts store say it should be?
Are you sure you are looking for the right part? It sounds like the rotors and hubs are for a four-wheel drive, based on your description.Why doesn't the brake disk on my truck match what ANY of the auto parts store say it should be?
Remove the wheel and the brake caliper and the rotor comes right off. That is the configuration for the '97, You may have an older model with the hub and rotor integral. Your vehicle may have been made in '96 as a '97 as earlier models had both configurations.