If a junk yard unit doesn't look or smell torched and spins smoothly, it is likely still fine, but I can understand your apprehension. At the very least, a trip to the bone yard would be good for taking measurements, etc, to determine the year/engine size Taurus that will best suit your needs, not to mention, a cheap junk yard piece would make a good test part for experimentation for trimming/mounting as opposed to randomly cutting up/modifying a new one. Remember that teh recommended alternator and wiring upgrades mentioned are not merely a good suggestion but an ABSOLUTE MUST when installing one of these fans. New Taurus fans are available fairly cheap, but a used OEM unit may likely have better longevity than an aftermarket replacement part. Also you could get a junk yard fan and then replace the fan motor after properly modding the shroud, saving you a few $$.
My $.02,
Gene