I was "318", when 318 wasn't cool......
IMO if it's over bored it should be noted.
It DOES change the displacement.
Most people are too lazy to do the math.
I have heard a few folks say things like "now it's 322".
I guess we can say the jury is out on if a .010 or .030 over is still a 318.
Again, I suggest an asterisk.
...but a 390 is most clearly NOT a 318, despite what the block casting says.