Anything is possible, so yes. It's multiple ways of screening and i say do every multiple way it is. You can never be too safe!
My understanding is that in any undercover operation anything goes. They do not have to tell you they are a cop. I think cops can even use drugs to secure a bust. So surely they could write a review. I think most providers would catch wind of being reviewed by someone they have not seen.
Even if the guy has several reviews you still need to ask questions. Talk to him on the phone for a few minutes and ask lots of random questions. If he starts asking questions about gfe, greek, kissing etc then hang up.
He is either a jerk or a cop. Stay safe!
Sometimes just by the conversation you might get a bad feeling. You need to listen to your gut.