to answer your question, the OE coil pigtails are part of the main engine harness. they do not separate. if one pigtail is broken then replacement Motorcraft pigtails are available via your local Ford store.
my two cents? save your money on the ignition junk. unless you have a broken component then none of these replacements will better your mileage.
the stock coils have more than enough jam to be able to fire off a good spark - and that's when the truck was new. as the truck ages and compression drops so does the voltage required to fire a spark.
save your money and spend it on fuel instead. drive with a lighter right foot, and if it has been a while replace your fuel filter, spark plugs and air filter. modern ignition systems leave almost nothing wanting.
2003 GMC Sierra 3500 -- dually, 4x4, hasn't blown up yet and that's what i look for in a truck
Ford Doctor -- They come in broken and leave fixed. Ford of Canada Master Tech