Bulova 1957 Beau Brummell

1957 Bulova Beau Brummell ( I believe it's the "I" variant although it states white gold not yellow. I cannot however find anything anywhere specifying yellow or any other variant of this design other than the "I" ). Movement is a USA 10BP 21 jewel. Kriesler band is period correct but not original. I believe these to be a 2 yr production. 1956 and 1957. I have seen several in White and all were '56. I have seen only two in yellow, mine, and the one currently listed in the database that states it is yellow, but sure looks white to my eye. Both of these are coincidentally '57. So perhaps a guess would say the '56 production was in white and the '57 production was in yellow?? I dont know. I just know it is a dial design not seen very often.