Recap won't import LGS, they are a particular Leica viewing format. AutoCAD can import them as a XREF with the Cloudworx plugin but can't convert them to anything from there. The only thing I have used that can convert them is Leica 3DR, though it may also be possible with Cyclone...
Unless those are platforms you have available, I would ask whoever made it to export you an RCP (or a PTS/E57 which you can convert inside Recap).
Use iLogic Copy? Please consider voting for this long overdue idea (not mine):https://forums.autodesk.com/t5/inventor-ideas/string-replace-for-ilogic-design-copy/idi-p/3821399