The lower brackets will bolt to the rear end housing. Since they go directly over the housing they have to bolt on rather than being welded because the threaded bungs on the bottom of the air springs are in the center.
The last modification for the frame was adding front shock brackets. Rather than making these, I bought the gas shock and bracket kit from Air Ride Technologies. There was still some work involved in trimming them to fit and ensuring that they had sufficient clearance throughout the travel of the front suspension and steering. I must have been so excited about getting the frame done that I forgot to take any pictures that day.