To an extent. Take the AMD Athlon 64 series, a 3000+ has a multiplier of 9x, the 3200+ 10x, 3500+ 11x, and so on. Im not sure about other cpu's though.
He means, are 3.0Ghz processors just like 2.8Ghz ones, just overclocked a bit at the factory... well in short, kinda yes, they arent gonna produce a whole different core just to step up a speed band. They are all the same, just slightly faster ach time, so yes, you could think of it as each new veriosn has been "overclocked" from the last one.