It would work but I reckon the duplicate would sound like shit due to the composition of the silicone rubber and the liquid plastic in use, which is intended for other manufacturing purposes and not hi-fi sound reproduction.

Otherwise this method would be more commonly used for small scale record production as it requires no large heaters/presses/other heavy plant.

The silicone would not be the best stuff to duplicate the very small grooves (it distorts easily and a fraction of an mm distortion would affect sound quality) and the diamond needle would probably tear the duplicate to pieces after a few plays anyway..