Hey guys, I've done hundreds of suspension lifts in 4x4's and lots of suspension work on stock vehicles in my 42 year career as a vehicle tech. Many times when the "U" bolts are made they "spring" out a little bit at the threaded end, and usually can be squeezed by hand to fit thru the spring plate holes. I should have said if the u bolt fits the tube properly then squeeze them together. Ive watched dozens and dozens of u bolts get manufactured, it's done in a press around a preformed jig, there is some margin for error.
I assumed that was the case in this instance, as Jim stated that the u bolt barely fit the housing, I should have asked for another picture to make sure before answering.