Passenger side is about a 1/4" thicker. You would never notice when they're installed in the truck, but if you have them side by side on the bench it is noticeable. People mix them up every now and then and end up with a lopsided truck. Below is a picture of a set of seats out of a 4x4 Bricknose when the swaybar mounts were integrated with the seats. The Bullnose seats are the same, they just don't have swaybar mounts.
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