My 2003 F150 RWD was wrecked about 6 years ago. Only the right side steering and suspension were replaced. It's developed into a fuster cluck. I've torn everything out. Ordered new Raybestos Advanced Technology upper contol arms, seem nice. However the Raybestos lower control arms were crap, plus the boxes from Rock Auto were miss marked and I received two of the same side. They were sent back. Figured I would rebuild the current lower control arms that are OEM. Leading edge of bushings have been peened over at 4 points. Assume these will need to be ground off to press out the bushings. Noticed they were not pressed tight to the flange, there is a 1'8" gap. Have new Raybestos bushings, made by Clevite. Guess I'll have to maintain the gap when I press in the new bushings. Haynes manual does not cover this. Any recommendations on how to proceed.
Saw a video on this but can,t find it again.

 

I took a quick look at my '97. I see the same 1/8" gap under the bushing flanges that you saw. I did not crawl under to look at the leading edge of the bushings, due to the late hour.
If the bushings new and old measure out to be the same length, then I'd probably copy the factory install.

 

The bushings need to be a given distance apart to fit into the truck frame. IF you push one bushing in too far, you can not reinstall the A frame. Try to push them in with the same clearance that the original had on the A frame. AN alignment will take care of minor changes in installation distance. THe bushing must fit TIGHT in the A frame hole, they can not slide around.