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.

8042447-kIMG_9730.JPG (136 downloads)
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.