It's a paint manufacturer number, but there are several paint manufacturers. Fleetwood sometimes changes suppliers, so not sure if that is a Sherwin Williams number of some other. A shop that specializes in automotive and marine paints should be able to cross reference it.
The difficulty with touch-ups is that the original paint will un fade as the years march on. My '04 has Lt Chestnut Metallic in an area subject to frequent stone damage, so I need to touch up regularly. That color is readily available in auto parts stores but the match is not good at all. I've had two professionally made as well with no better results. Finally got my front end repainted and kept a small jar of that paint for touch up. Will see how long it continues to match.
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC