'Evening suit' is not a common phrase in American-style English, though, I am sure the meaning would be clear to anyone.
Also, "have got" is not an especially highly regarded use of the verb, 'to have.' Normally, 'Have you formal attire?' or 'Do you have a formal suit?' is preferred. I was corrected on that by a counter attendent in Bermuda, where all the natives spea
Ed, where do you live? I've never heard or read the phrase "black or white wear" in my life, except for a local charity ball where nothing but black or white gowns for the ladies is permitted (true - I know a woman who thought she'd be daring and wear red but was turned away).
Also, don't let some Bermudan counter attendant shame you for using the perfectly correct "have got." Moreover,