Truck Repair: changing headlight bulb, sealed beam headlights, replacement bulbs

Question
I have a F-350 pickup. Having difficutly in getting the headlamp out to change a bulb. Instructions say to remove the lower clip, but I can't find such a thing. Is there a trick?  

Answer
Hi Tom,
Before 96, back to about 87, they mostly had composite lights where you replace the bulb from behind.
Then they changed back to the older looking headlamps, where you replace the complete light assembly, quite a lot like the pre-87.
But I don't know where a lower clip might be.
If you open the hood, and above the headlights look for a thin metal flat strap looking thing sticking down through the core support. Actually, there may be two for each headlight.
It could have an "L" shaped end there at the top of it. Gray, unpainted metal.
If you have them, and the composite headlight housing, pulling up on the "L" shaped top, pulls that strap, which is a retainer, off some pegs on the headlight housing. Then the complete assembly comes out, and you remove the replacement bulbs from behind.
That type has a large plastic lense, rather than the sealed beam headlights.

Van