Polyamory

I want to preface by saying I've been poly since 1986, but I have never been socially smooth, so I can't tell if I'm missing something. I met a couple over the weekend at an event. The woman was very impressive, and the guy was looking at me like I was a miracle aglow. It felt like they were poly, but I might have been making it up. I know lots of monogamous guys cheat, but wouldn't he be a little more hesitant in his admiration if it was not allowed and she was right there in the conversation? I didn't exchange any contact info with them, but a mutual friend invited them to another event next week, and I told them I would be there. What do people do in this situation? Just ask?