Requested Ultrasound..

Hey ladies, just a question maybe someone could help me with. I have an appointment on the 30th. I will be almost 17 weeks. The apt is only for a regular checkup. I was wandering if I request an ultrasound would they do it. Bc this is the last apt my husband is going to be able to make for the next few months and I want him to be there when they do the ultrasound. But I don't want to wait 3 or 4 months to find out the sex either...any thoughts?