Can't speak with authority on this, but I'd be suspicious of a saw missing its ID tag, unless there were serious scratch/scuff injury to indicate it had somehow gotten ripped away in use. And that would seem pretty unlikely.
FWIW, I bought a Husqy 371, Craigslist find, where the owner did not want me coming to his home, and we met in a convenience store parking lot. Plenty of people are rightfully wary of letting CL strangers come to their home, so that didn't bother me. And the seller and the price all seemed legit (guy drove a Cadillac, several years old), not like some lowlife, and it took several days for his work schedule to open up where we could meet. Good saw and I had it running well in the parking lot. A few weeks later when I cleaned off the grime I found etched into the saw's plastic cover a guy's name and town in another state. Pissed me off to think maybe I owned stolen property. It took some real internet sleuthing, but I was able to track down the guy with the etched name and called him on the phone. It turned out he'd sold the saw some years back, but he appreciated my call. And I appreciated that I did not have a stolen saw.
