Remember also, there are both steel and aluminum versions of the double, the aluminum being the later.
Steel and aluminum aren't the only distinguishing features. Pre war mounts, whether single or double lever, had bases which were cantilevered inboard and were fitted with 22mm rings. The later mounts were cantilevered outboard and could be fitted with either 22mm or 1" rings interchangeably. Noske also made mounts only for his 22mm scopes, and most had double locking features.
Incidentally, with the proper tool, the double lever levers can be properly adjusted to line up when locked.
