[SCOTI]

Can you get some pics of the hangers @ the front of the leafs & the shackles @ the rear?

Typically, just flipping the rear-end from below to above the leafs yields 5-6" of drop. At 6" of drop, there should still be about 1-2" gap between the rear end axle tube & the bottom of the frame rail.

Add some dropped shackles & you get another 1-2" of drop.
Remove the leaf & it will drop another inch (possibly).

Installing an AOL set-up can be done cheaply. I bought a piece of 1' x 1' steel from Lowes for < $30. I was able to cut it up & make my top brackets for both sides. I used the original leaf pads on top of the rear end as my bottom brackets. Add the air bags & I did it for < $200. If this guy you met has a decent kit, it might be worth the money (depending on what type of brackets it has, what type of bags, & what else is included).