I haven't checked mine to see if it has the fitting, but while hovering over Maxx's W250 (non-I/C) yesterday, it appears the post-filter banjo (feeding the IP) is already tapped/plugged. Could this be used for an fuel pressure guage?

If so, any chance my I/C'd setup has this?

I figure it could be a helpful diagnostic tool for fuel related issues going forward...

 

That is a bleed screw, your truck will have the same thing in the same place.

 

So...

OK to use for fuel pressure line?

 

No reason you can't, although the little bolt is metric, they do make one that are drilled and tapped for 1/8 pipe thread. Geno's carries them I think.