Yes I agree with Taximom5, you should ask and have every right to see the packaging and insert that comes with the vaccine.
I've read the majority of the severe cases of HIB in children happen under two years old. It is entirely up to you to weigh the risks of HIB or go ahead and get a booster. Since she is preschool age she wouldn't need more than one booster shot if you decide to go that route. The single HIB shot is only approved prior to age five so you have a couple more years to decide if you decide to wait.