My old Zeiss Dialyt 7X42 B/GA T*P's are still my favorite binocular for birding despite more modern choices. They just feel right in my hands. Long story short, I couldn't resist a good price on a clean pair of Zeiss Dialyt 8x56 B/GA T*P binoculars as a stable mate. Serial Number: 392512. Could someone help with dating them?