Yep, common as dirt. On my 06 SWB CC, I took it to have a bed cover and lowering shackles installed. The installers immediately got out there tape measure and checked the height, bring it to my attention.
It seems that they had so many people complain that the shackle was causing the problem, they started bringing it to the owners attention "before" they installed the shackles.
Mine was so bad that I have one shackle set on 1" and the other on 2" just to level it out.
James- Thanks for pointing it out that this was in the wrong forum. I didn't catch it either until you said something....