NO....that does not mean that everything from the years covered in the manual is completely interchangeable. The Haynes manual covers general instructions on how to do things, but does not mean all the parts are the same.
You could have 2 completely different parts, but are removed and installed the same way. Take a manual transmission for example. You could have a T18 Warner or a Clark 4 speed OD. The manual is going to give you instructions on how to remove and install both of those pretty much the same way (those actuall have different shifters so they would be a little different) but that don't mean they are the same part.
Best thing to do, go on a part store web site and look up the part for different years and see if they give you the same part number.
I will look in the Ford Master Parts Catalog and see what I find.
You are saying it originaly had manual steering? I wouldn't have thought any of these trucks had manual steering from the factory.