Perhaps that particular salesperson had not but he/she should have been briefed on it and should be familiar enough with deployment status to be able to talk intelligently and honestly with a potential customer.
I could buy that if it weren't for the fact that it took two days to come back with that answer. An off the cuff "wow, nobody has ever asked me that before, I need to check on it" would have been understandable for a new rep. Two days later coming back with "gee, we really haven't had anyone ask about that before" is bogus. I am not trying to beat anyone up here, the point is a general one for the providers out there. If you can't offer v6, say so, don't try to dance around it and pretend that customer is the only one on the planet with a migration plan because we know better.