The first Alaskan's had adjustments that were open to the elements, then they added screw on caps "all weather" to protect the adjustments. The "all weather" markings were also found
on the Lyman Challengers, and I believe, though I don't have one, on the Wolverines. The All-Americans came later, and the perma-center All-Americans had centered reticles. Nick Strobel's book on scopes and sights is a great reference.