I have a 999B serial number 1B794 it has a silver balance with silver spokes. I was told this is an Elinvar. Is this true? After researching I do not see any 999B that are refered to as Elinvar and I am asking. Also, what is the difference between the gold balance on a 999b and the silver balance on the 999B. Thank you and I am sorry if this is a dumb question.