Question about gas tank/sending unit replacement

[72Ken]

Hello all. Newbie here and needing some help. I tried searching some old threads but didn't have much luck finding out what I needed, forgive me if this has been explained already. Purchased a 72 C10 years ago and shoved it in my barn. Finally getting around to tinkering on it. Truck appears to be all original with 307 2bbl and Auto trans. Ordered a new gas tank--matched up that mine has EEC, and ordered new sending unit--matched up that I need the "72 with auto trans". I install new tank and notice there is an extra hole punched in the top for a bolt (no problem). But also notice that there is not a threaded hole for the fuel line to secure to (see pics). Also the old sending unit only has one line and the new unit has 2 lines. Like I said everything seems to be original but I could be wrong. Anybody ever come across this before? Im sending the new unit back to get the "manual trans" with single line.