The GSX Jetway replacement files are used to replace jetways in default airports that had default jetways, and the reason why you might need to move some airports on the right, is to PREVENT GSX to replace jetways with a file meant for a default airport, on 3rd party airports that will surely won't match.
But since LTFM is not included in the default scenery, there's no jetway replacement file for it, so you don't have anything to do to protect the add-on scenery you have from having its jetways being replaced by GSX.