You're going to have to get crafty to fix those because, as NskLJ noted, they are molded into the tank. I ran into a similar (but not the same) problem when I rebuilt my Expedition late last year. Mine had a small crack that was throwing an evap code, and I found a two-part epoxy used to seal aircraft fuel tanks that seems to have sealed the crack and solved that problem. One of the downsides of all the emissions requirements is that it's getting trickier and trickier to keep old vehicles running because certain parts are simply not available. You may have to plug that and glue in a new fitting or cut off the remaining nipple, drill and tap it, and install a barbed-to-npt male fitting to connect to the vent hose.
