Not sure IF the 41's are like the 46's......I got mine for the 46 from EMS/Bitchin' products and those were three piece (Fronts, middles & rears) and yes you had to weld them together OR piece them back in one at a time tacking the joints/junctions until all three are fitted just so!!! Fortunately I had very solid floors and good solid front boxes SO all I had to fit was the middles and rears. The EMS pieces also had plates to help strengthen the floor to rocker box joint