No...
As I said previously: "That item will always be a solid box (or solid box with hyphen - same thing) whether zero, some, or all files in the folder have been marked read-only."
In other words, when you open folder properties and look at that box it tells you... absolutely
nothing.
The box only
temporarily has meaning when you check it or clear it and click OK or Apply. It does not show any status whatsoever when you open the properties dialog. It's a misuse of a checkbox. It should have just been a button with a dialog, or two buttons, anything but a checkbox that makes people think their folder is read-only when it is not.
I know it's hard to believe that a checkbox could exist that doesn't convey any actual status, but there it is.