I know most people just take the existing banjo bolt from the supply line into the pump and tap it for a 1/8npt.

Is this from Diesel Manor the same thread that we have on the 12 valve?
I'd like to use something like this as it has more 'meat' on the bolt head.

http://www.dieselmanor.com/dm_products/DM-DBBLT.asp

 

Dont know about the banjo but I tapped the FF housing. There are two dimples in the top of it(my 98.5 had them tapped with pipe plugs in them already wonder why?) The one farthest to the front is post filter.

 

The stock banjo has plenty of meat to tap into.
Besides that the tapped banjo from diesel manor is for a 24 valve, won't work on a 12.
I've never seen any sources for tapped 12 valve banjos.