Depends on your significant figures as well. The percent difference between those two numbers is 0.067%, which is pretty darned low for any statistical significance anyhow.
Also, 2.998e-8 isn't correct either. There are lots of digits past that, so therefore by rounding up to 2.998e-8 you just violated relativity.
And, I think they have taken a few photons past the speed of light. In space there is a mild resistance; space does have substance (a few months ago PopSci had some issue about future space travel and one of them was that solar sail thing). So, if in a pure noble gas vacum you may be able to exceed the speed of light as found in space.
Or, something like that.