Yes they are waterproof! They are built to the highest standards in the optics market! Even tighter quality/fit tolerances than Nightforce, or Schmidt and Bender.
I'm no optics guru, but I believe that if an optic is fogproof, it is sealed, thus also waterproof. However, a waterproof scope isn't necessarily fogproof, as it could be sealed without the oxygen being purged and replaced with nitrogen or argon.
At the bottom of the spec sheet on this link, indication is that all March scopes are argon gas filled:
Danco411 just saw your post! Thinking of how we could adapt amphibious swimming qualities and started laughing! I think everyone on here would die laughing if that was possible!