Which preset are you speaking of? I have one called "geoencoding," but I'm not sure if that was a LR preset or one created with a plugin I have added.
I would think if GPS is in photo metadata (RAW XMP or JPEG) and shows up in Bridge it would be available in LR as well; it's in a standard place in the data (GPS IFD I think). Maybe you didn't refresh or reload the metadata for the photos in LR, so it doesn't know it's there? You shouldn't have to manually fill in anything; it should just be there as written by the camera. To test, take a photo that does not have geolocation info and add some in the Map module by just picking a location at random. If that works then look at the info in the Library module under metadata "EXIF and IPTC."