In general, yes. What you have to watch for is that the f-150 coil seat doesn't lift the front high enough so that you can't keep the camber aligned.
If the front end dropped one inch with the bumper weight, the coil seats will actually lift the front slightly over where it was before the bumper. That means you may need an alignment (camber at least) but it didn't lift it so much that it will throw you to the point where it can't get aligned.
In short (I know, too late) it depends on how much the bumper screwed up the alignment (lowering) compared with how much the coil seat will mess with the alignment (lift).. But putting it under a lift coil is safe.
~Mark