Offshoreonly.com - Scarab 22 Gas Tank Fitting

Just posted in the Scarab section but thought I might get some more info here as well. I am in the process of upgrading fuel system and was wondering if anyone knew how the fittings are in the tank. I got the 90 degree fittings with the dip tubes out but need to take the fittings out of the tank to remove the reducing bushings. They don't appear to be a bulkhead as I can see what appears to be a molded boss below the fitting so was wondering if they are a NPT or o-ring (ORB) fitting? Thought I would ask before "f"ing something up. By the way, it is a plastic tank. Thanks.