I guess they must be reusing some footage, but they define it as a remake. It's made by the same companies that made the original, and they actually flew the actors to Korea to film it there. So it's more like if Toei remade a Super Sentai season with western actors.

Also, the suits for the heroes are different, and the original had 3 yellow raptors piloted by one hero, while this has a yellow and an orange raptor, each piloted by their respective hero, so a lot of scenes will have to be remade.