I have a Leupold 6x18x40 xiic scope. Does anybody know if the 40 mm Leupold alumina threaded lens cover will thread onto the scope's sun shade or will it only thread onto the scope 's front objective? I don't have any lens covers yet so I'd like to get a good set to take my rifle to and from various silhouette shoots starting this spring. Any help/input would be deeply appreciated.