For OGTT it will comes with only doctor's consultation and no scanning. They will provide results of the OGTT and perhaps include baby's heartbeat but not scanning. They will definitely have another scanning at about 28 weeks or so. You may eat more and interact so your little one can be little more active and you can check the gender as well. For scanning, it will require appt as it will be at different clinic and subject to availability.
Your gynae will tell you baby’s gender if they can see (provided baby have to cooperate). I knew my gender at Week 13 cause my baby’s butt was facing up.