The Dakota trucks went to the 6 bolt wheels in 1991 (1990 was still 5 lug).
The 91 to the end of the 96 model year is just a rotor change on the front, but all the early Dakota's (88-96) had the same size front brakes (only the rotor bolt pattern was different). If you currently have disc brakes, what you have is as big as they got until at least the 1997 model year.
In 97, Dodge went to the sealed front bearings. Those DO NOT interchange with the hubs and bearings on your 88-96 spindles. I DO NOT know if you can get away with just changing the spindles (and everything else between the ball joints), or not. You may run into needing the control arms (and more parts) as well. A 97 is way different then a 96.
Everything on the Dakota changed between 2004 and 2005.