Brunei $25 stamp 1910

Yesterday, I was off to Gadong during lunchtime and drop into my friend who deals with antique books. I was not expecting to buy anything but normally just have a quick look around at whatever new that he has got. Maybe I shouldn't say new. Whatever old things that he managed to acquire recently.When I was there he showed me these 4 stamps:-These stamps were issued for the Brunei Postal