I believe that kit #26133-07 includes an adaptor plate that goes behind the oil filter for the sending unit to screw into.
You will not need that kit if you install the sending unit in the oil pan using the pipe plug hole next to the oil drain plug (item # 15 in the attached link)
You will need an reducing adaptor for the sending unit to screw into the pan. I believe the correct size adaptor needed is 3/8 NPT external-1/8 NPT internal thread. I would pull the plug and take it along with the sending unit to the parts store to match them up with the correct adaptor.
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