I was browsing the US Anodizing website and noticed they offer a US Navy service anodized coating. Are Navy M16's and M4's really coated differently than all the others?

This what it says on there web page

US NAVY SERVICE: This service is available to complete firearms or components. It is intended for any firearm subjected to extreme conditions. A "must" for Military or Law Enforcement applications!
• All parts will be Anodized or Phosphate coated. (Mil Spec).
•All parts will be top coated with our Xtremcoat™ (Ceramic/Moly/Teflon).
•Friction contact surfaces will be coated with Xtremcoat™ (Dry Film Lube).
•Parts exposed to high heat will be coated with Xtremcoat™ (Heat Barrier).
These coatings, meet Military requirements for saltwater exposure. Test conducted for 500-hour salt spray (5% salt), the equivalent of a seven-year exposure. The same coatings are used on US Navy, Special Operation (SEAL) weapon systems