YES, If I remember well, the ears that came with the bike were knackered. these ears could have come from a 500t as I bought one as a donor bike for the forks, wheels etc but have since learned that the 500t rear drum etc is not the same as a 550f as the sprocket I bought for it did not fit. Knowledge is everything, lack of it is expensive! I will have a look at a 500t to see what should fit into these holes.
Peter