Where everyone dresses as if they are Klei Kodesh
what do you mean by “klei kodesh” here? Like the gedolim? I never thought to ask, but I imagine that since the gedolim tell us what to do, they would have made their opinion known had they not wanted us to dress in the same colors (or lack thereof) as them.
and on weekdays as if it is Shabbos
As far as I know, everyone who dresses in black and white- Chassidish or Litvish- has different Shabbos clothing for Shabbos.
So what you are saying is that you would not attend a black-tie reception during the week?