Buckle blue or white....... neither, brass. You are confused Baal. The 'slings' or straps were USED to make the scope box slings. Not 'as is' but cut sewn and buckled.
And they weren't that colour either Baal. Our issue slings were light tan in colour. The spec stated the chemical protection required and colour. That's what the spec asked for and got. Some slings in my knowledge came through in a light grey 'chrome' finish. This wasn't 'chrome' as in metal but the chemical protection during the tanning