You can get the OF version from "dev /openprom .properties" and 
looking at the model entry.  I've gotten:
Open Firmware, 1.0.5		on a PowerMac 7500
Open Firmware, 2.0.1		on a PowerBook G3 Series (PDQ)
Open Firmware 3			on a 450 MHz G4 tower (AGP Graphics)

Give or take commas and dot-revs it's the same on all OF versions.

I don't know why this was important, but someone said it was.
-- 
The opinions expressed in this message are mine,
not those of Caltech, JPL, NASA, or the US Government.
Henry.B.Hotz@jpl.nasa.gov, or hbhotz@oxy.edu