That's a very good question and would depend on how it's being presented is my assumption (and only an assumption). If you're presenting it as a business card type presentation, or giving it away to advertise, then it may be considered commercial. If they buy your print and that's how it comes you'd be in different territory because they purchased the print, logo and all info on the back, and you didn't print it on your own for promotional purposes without them knowing. So again, it's an assumption but if they buy it and you place that stuff on there - good. If you print it on your own for promotional purposes (advertising) without them knowing before hand - bad.
As I've said, personally I don't see a big problem but when you run a business you have to always plan for the good and bad, the good cases and worst case scenarios. Seen to many situations already where something little that you think noone would get upset over gets blown into a big deal.