I have a Full Traction brand 6" lift that is for the 2500HD trucks on my 2500. So, if it's a good deal and in good shape jump on it. If you know the manufacture, go to their web site and see if you can print out the install manual which should also have the parts lists so you can see if its complete or missing parts which may or may not be available.
Our Av's pretty much will swap most suspension parts with the trucks, Suburban's and front end parts on the Hummer H2's. The H2's 14 bolt rear end will swap to 1500's with shock bracket modifications if you want a stronger rear end.