Yes, you can use the same account for both official Whatsapp and OGWhatsapp APK. But the only problem is when you try to log in to your account, another Whatsapp app will not work. You will need to log in again, and the same thing will happen again so that you can use one account at Whatsapp and OGWhatsapp at the same time. But still, you can use one account if you have enough patience to get in and out again.