If they have been building it, the parts probably match the datasheets.
If every thing was done by outside contractors, of course there will be no libraries. Or consistency from board to board. My suggestion would be to just leave the existing designs as is, unless there's DFx problems. Start your own library for new designs, don't try to build it from old designs. Especially if you need to go from Logic to DxD. It's not a real clean conversion, if you aren't losing years of libraries, it's not worth the effort.