Getting the question right then being offered recording dates is standard for just getting the question right, like many of other people will.
As someone else says, there is another process. Then you have the day out doing a rehearsal etc then have typically a 5-1 chance of getting on (ie 2 people in contentants row usually in one show with another from a previous show). Then you have to get 15 questions right!
It's a good day out even if you don't get in the chair.
My tip from one of the production team at the time I went there was, if you get a question right and a list of days, go for an unpopular day like Tuesday or Wednesday as they get less response from those days.
Good luck