Paint codes with gel-coat? Not my experience.... my 2001 NationalRV Dolphin,the gel-coat got oxidized beyond repair. Took it to a paint shop. They asked to look at the "spec sheet" (located in the closet) but there were no paint codes. The shop researched on their computer....no codes.
The painter spend quite a long time trying to match the paint. He did...and did well. He told me the reason there were no codes is because the gel coat was never "painted" The color was IN the gel coat.
My experience...FWIW.