It looks like the plugs you removed have a platinum puck on the ground electrode, though they look worn and one looks like it's almost gone. Did the replacement Motorcraft plugs have a platinum puck also on the ground electrode? I purchased Motorcraft plugs for my 2.3 EB to replace at around 30,000 mi per BDCardinal's observations at his Ford dealership. I haven't removed the factory plugs yet but the Motorcraft replacement plugs, CYFS-12Y-2, only have an Iridium positive electrode, no platinum puck on the ground electrode.
Whimsey