Yep, 91 was the first year for the 6 bolt wheels. 91 through 96 can be converted to 5 bolt at the front by swapping the rotors. The rear can be changed from 6 bolt to 5 bolt by swapping in the 5 bolt axles from the same size rear end. Dakotas used a 7 1/4, and the 8 1/4 (also called an 8 3/8") in the early 5 bolt pattern years, and a 7 1/4, an 8 1/4 (8 3/8), and a 9 1/4 in the 6 bolt era. I have no idea what they did with the "new" 5 bolt wheels, but I suspect they used the full size truck stuff.
With the 97 model year, the front wheel bearing design and parts of the front suspension were changed making the swap to 5 bolt very difficult on the front. I have heard there were some issues concerning the axle "C" clips involved with some of the 9 1/4 axle swaps, but there hasn't been a clear understanding of what those issues are for sure. It seems some have had issues, and some have not.
The 6 bolt pattern Dakota was around for several years, there are a lot more wheel choices then there were years ago. Its also the same bolt pattern used on a Viper. Gene
