Yup, one of my gumdrop iMacs is using an WaveLAN Silver card that was pulled out of my original AirPort Base Station when it died. Took some effort to shoehorn it into the AirPort Adapter, but I got it in there - OS recognizes it as a "true blue" AirPort card just fine.
I've used WaveLAN Gold cards just fine in PowerBook 5300, 1400, and 190s. I tried to get it to work in my 540, but I don't have the right version of the PCMCIA cage.