Dave,
The 87-90 Dakotas have the 5 on 4 1/2" bolt pattern. The 91-96 (I believe) use the same suspension but have 6 bolt wheel pattern. This era you can change the bolt pattern by simply swapping in the older parts. The 96 and newer also have the 6 bolt wheels, but changing to the 5 bolt pattern requires much work. Beyond the year 2001 I know nothing about.

Dakotas cane with 4 cylinders, v6, and v8s in 4.7, 5.2 or 5.9 versions. Trans choices were 4 speed, 5 speed, and od autos. Rear axle choices were 7 1/4, 8 3/8 & 9 1/4. All had rack & pinion steering, front independent suspension and rear leaf springs. Not all engines choices were available every year, and not all trans choices were available with each engine. As I understand, the early trucks had 2 frame wheel bases available, a 114 and 129. Newer trucks had 3 wheel base lengths available. Don't know when the 3 wb started, but I suspect around 94. Gene