Slobo

This may be a dumb question so let's rip with the dumb answers.

My understanding is that officers' cap badges and chinstrap buttons on SD peaked caps (and field service?) were bronze or blackened metal, even when buttons, etc. with gilt or brass (i.e. dark vs. bright). Is this correct? Was it by regulation? If so, was it frequently ignored? I am particulalry interested in the immediate pre-war/early war years. If not by regulation, or if by regimental discretion, were there particular regiments that specified or otwrwise were known for bright badging and buttons?

Does anyone have a WW2 Commissioned & Warrant Officer (CW) candidate blue round cap, or at least the white capband, in their collection?  Detail photos would be great as well as description. I'm looking for details on this arcane but overlooked item, such as how it attached (no knot), fabric, etc.