Well look at pics online of the explorer intake/gt40 intake and look at yours. They are impossible to confuse. If the lower is a GT40 style and it has the bung already tapped in #5 then its either an OEM Cobra lower or somoene tapped it already. Either way you can just relocate that sensor to the inlet tube if you don't want to drill/tap.
As far as the intake swap itself, very straightforward, as long as you have hand tools and a torque wrench you are good. Google "explorer intake swap" and you'll get multiple install threads/guides.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.