No, they sit on the leafs by a U bolt and then bolt (or in my case I welded it) to the frame. I was looking at that after I posted to see if they would work for you. Nope. But the heavy duty ones, the 5000s sit on the axle and bolt to the frame, they should work for you.

As a side note: I have a hunting buddy who bought an '09 in November, we took 4 ATVs on a large dual axle trailer hunting and used it to tow on the way to hunt. I'm guessing somewhere in the 4500# range with trailer. Hit the bumpstops constantly and was all over the road. We ultimately hooked up to an F-150 for the trip back, it was so bad.
The F-150 with over a hundred HP less, handled the load like it wasn't even there. Pathetic!

 

As others said you really bought the wrong truck for that. Heavy Duty for 5th wheels. 3/4 ton plus trucks. There is more than "bigger" springs that makes a HD an HD. Safety first.

 

In hindsite I guess the 3/4 ton would have been best but there must be a way to help you, 1, you seem to be at 1400 lbs about 400 lbs over a half ton so as far as leveling your truck I think it is doable, part of the problem with our trucks is this year it was designed to sit level with no load unlike earlier models that had a foward rake built in, since many trucks and most semi trailers and city buses all use airbags I would recomend just going to a higher rated airbag, you could probadly sell your current setup pretty easy as many like me are planning an upgrade to an airbag but don't need the real big one, my trailer weight at the hitch is close to 700 lbs so I expect it to drop some, remember, when its level to start with any weight will cause the rear end to drop below the front,I wouldnt be surprized if Dodge didn't offer some sort of helper bag in the future, as far as the rest of the truck being to lightweight like you said you have pulled before with a half ton, as long as your trailer brakes are working good you should be ok, I suspect many pickup/camper comos are legally overloaded time u count gear, fuel, and people riding in it, I have a bro-n- law who runs a truck overloaded as a lot of them do from time to time, let us know how it works out and u could probadly sell your old system here

 

I dont know if you saw my post in your other thread, call airride, their rated for 3000lbs each so that should hold you over.