TBH, I didn't examine it that hard, it just *looked* cgi to me. I could very well be wrong.
Weren't most planets in TNG done with early CGI anyway? I remember a story where one of the effects guys parked his car when he came into work one morning, stepped out, and stood in dog poo. He was understandably annoyed, but when he looked at the poo, the texture his shoe had created on it was interesting. He snapped a picture, scanned it, and used it as the surface texture for a planet.
I remember spotting pixelisation on the surface maps for planets in the first and second seasons. Really early CGI work, mapping low-res images to spheres.
I'd imagine all of those will have to be re-rendered, and probably re-textured. The hunt for dog poo is on!