Lightroom is generally only displaying the lens information already written into the file by the camera. It does not normally rewrite the EXIF lens model data for you.

With some Sigma lenses, the camera-recorded lens ID can be less specific than with Canon lenses. Sigma has reused lens IDs across different models, so the metadata may only identify a lens in a general way, such as its focal-length range.

That’s why Lightroom may show incomplete lens information on import, yet still pick the correct profile for lens corrections. Lens correction can use additional clues beyond the basic lens ID, such as focal length and aperture, to infer which Sigma lens was used.

So in short: no, Lightroom won’t usually “fix” or expand that EXIF lens designation. If the file only contains a generic Sigma lens ID from the camera, Lightroom can display only that, even if it can still make a good guess for lens corrections.