When I was dating, I used to be disturbed when a total stranger would sometimes call me up, saying she/he was a shadchan, and would want to set me up- not knowing me, what i was looking for, and would be vague about where she/he even got my name from. I would not use the services of a lawyer, real estate agent, psychologist etc without a recommendation that the person is competent and fits my need, so how much more so a shadchan!
I don’t think it would be proper to interview him in person, but for sure before you agree to meet him and “hear” proposals from him, find out about him, what is track record is, what type of people he knows, how easy it is to talk to him, etc. You can ask this person you know these questions.