No.
The impedances of the individual drivers vary, and they are all connected in a complex of crossover networks that also have a lot to do with the overall speaker system impedance.
There is no way to make any general statements of that kind because every design is unique.
The number given on a spec sheet as the "speaker impedance" is only a very general approximation anyway; it tells you very little.
Every speaker system has a different impedance at every audio frequency, and the only way to know this in detail is to view a GRAPH of the speaker impedance VS frequency for EACH speaker system.
Look at the Stereophile website and check out the "Measurements" section of a speaker review from a past issue. They always give a graph of Impedance VS frequency for each speaker reviewed, as well as other useful graphs and measurements.
A typical "8 ohm" speaker system may have an impedance of 5 ohms at some frequencies and 20 ohms at some frequencies.
The drivers used in a 4-way design might be chosen because they have somewhat higher impedances, so that the overall speaker system impedance does not end up being unacceptably low.
The driver and crossover design possibilities are infinite, and so the graph of every speaker system's impedance will also be unique.