Tux question

Hi girls, I am full of questions today

Ok, here's the deal. My FH is wearing a black tux, with ivory shirt, vest and bowtie

The ushers are wearing black tux with ivory shirt, latte (light brown) vest and bowtie (to match the girls dresses)

My question is we want to make sure the BM is recognized as the best man. Do you think it is ok to have him wear a black tux, ivory shirt, latte vest and ivory bowtie?

Or if not, how do we differentiate the BM from the other ushers?

TIA

Stephanie