They are selling you Dakota dropped spindles and likely ripping off info myself and others discovered many years ago. Heck, I talked to the engineers at Bell Tech back in the late '80s/ early '90s about using their dropped Dakota spindles on my '81 Ram. Here's the short of it...
-Rams and Dakotas have bolt-on steering arms.
-The Ram arm is longer than the Dakota arm.
-Dropped Dakota spindles have the steering arm cast into the assembly.
-The cast-in arm is shorter than the stock Dakota arm to clear the wheels (and I believe 16" wheels were required...which were large in 1990!).

In short, the dropped Dakota spindles have steering arms that are 2 steps shorter than a stock Ram. They can be made to work but expect some interesting steering response.

***This has likely all been covered somewhere in this and/or other threads.
In the late '90s/early '00s I had made a chart on several ways to drop a D series Ram. Don't ask for a copy as I have no idea where to find one but it's floating around on the Interwebs somewhere. I rarely have a chance to poke my head into these threads anymore and I doubt my truck has seen 200 miles in the last 5 years. Sorry.