Quote: My recollection is flawed. I have been lately working on my RMS K, and it has a 1.75 opening in K member attaching bolt tube. Below is a 2x3tube next to I believe a typical OEM K. The opening measurers 2.72" in rear and 2.39" in front. OP's front with 2" sq tube is a smaller area. However very importantly there is on all attaching bolt areas a third vertical gusset, 1" from bolt hole center on the third side, and provides most of the mounting surface reinforcement. The pictured OEM flange thickness is .285", with dirt/rust.
So a factory is a little more then twice as thick in mounting flange then a 1/8 box tube.
There is an extra L-shaped piece welded in the hole area. The total of the main plate thickness and extra L-shaped piece make up the approx 1/4" thickness.
