Is this a date or just dinner with a fellow employee?

About 2 weeks ago at work a guy transferred in from a Australian sister company to help out with a project. I was his temporary secretary until they hired him a permanent one because my boss was out of town at the moment. He told me on the first day that I had a pretty smile and I became really flustered over that, to the point I am positive I turned completely red. Everyday he would say something really sweet to me. He always made it a habit to touch my hand or sit really close to me. I am no longer his secretary because my boss is back and they hired him his own. He asked me today if I wanted to go out to dinner when I went to pick up some of my stuff that I had left. I said yes. Is this date? Should I ask him if this is a date? Or is this just a fellow employee taking another fellow employee to dinner?