I believe that is a Ranger and/or Bronco 2 tank? It looks the same as the one in my truck as well (which isn't a Bullnose tank so I'm told). I think the two mounting tabs are the clue here? Are the tabs on the Bullnose tanks sticking out the left and right hand sides, and not the top?
1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995