Are you talking about lifting the front or lowering the back? a rear lowering kit (shakles) should work because the rear end uses leaf springs on both. A front lift kit would be different because the front end is where 2wd and 4wd are different. If it has anything to do with struts or spindles it wont work because they are different. Any kind of spring spacer SHOULD work but it might not be the correct height. A 4wd sits higher stock than 2wd so you would need to lift a 2wd higher to get a level so a 4wd kit might not lift it high enough to get a 2wd to sit level.
Did you find a good deal on a 4wd kit or are you just having trouble finding a 2wd kit? There are lots out there if you need help finding one let me know.
2007 Black Dodge Ram SLT QC/SB
DIY is the way to go!