The official ANSI & NFPA standards body for RV construction is the RVIA (RV Industry Association) and they do indeed have publsihed standards that all members adhere to. It is ANSI/NFPA 1192 and ANSI/RVIA 12V (low voltage power systems). There wil be an RVIA seal somewhere on complying RVs. It probbaly doe snot go to the depth that you are describing, though. It deals mostly with safety concerns (e.g. LPG, Smoke and CO detectors), measurement methods, plumbing & electrical systems, that sort of thing. Except for fire safety concerns, the materials and construction methods are, I think, mostly up to the manufacturer.
RVs also comply with relevant federal vehicle safety standards, the National Electrical Code (NEC) and National Fire Protection Code (NFPA) for the year in which it was built and the EGS-1 standard for generators.