New to Buicks

This might be a dumb question. Aren't the Buick GN/GNXs and Regals basically the same chassis? If so, how much work would it take me to get the Regal looking like a GN/GNX?

The Grand National's are Souped up Regals up to 1987 GNX im not sure about
long time ago i knew a guy that turned a white 84 regal into a GN. Looked authentic to me