As far as I know, like googy said, admissions committees don't really distinguish between high level grades. There really isn't much difference between GPAs above 3.8, in my opinion. At this point, I think grad schools care a lot more about other factors than a 0.1 difference in GPA.
A first class honours is the highest level of achievement, right? I would interpret this as equivalent to a 3.8-4.0 in the US scale and therefore I would say that you should not feel limited by your grades when you apply to schools. No need to worry about it