King,

Parkerizing was popular with the military during WWII. They considered it a "tougher" finish than bluing.
http://en.wikipedia.org/wiki/Parkerize
http://www.calvan.com/html/what_is_parkerizing.html



Brownells suggest that the best results are achieved if the firearm has been sandblasted. I have never heard that it was better in a salt water environment.

This is the link for Roguard:
http://www.robarguns.com/roguard.htm

Pete