They are also used on the B200 and B300 Vans, not sure on the B100's. I have them on my B300 with a 70 340 attached and a short filter fit with the brackets on. A longer filter will hit the frame.
My Duster had them originally, been off for at least a decade and haven't had any issues. I believe my D200 has/had them but I may have removed them as well since adding headers. Would be nice to know exactly why those were implemented, from the Chrysler engineers.