No, you will not be able use Facetime on that device in the US or Europe. Apple is only doing what is required by the governments in those regions and has nothing to do with limiting the devices ability to use facetime themselves.

Is FaceTime allowed in Oman?

In 2012, Oman's telecom authorities reportedly unblocked some voice-over Internet Protocol (VoIP) services. ... Oman's neighbor, the UAE, is yet to lift its ban on VoIP services. Popular video calling apps such as Skype, WhatsApp call, and FaceTime are officially blocked in the UAE.

Does iMessage work in Oman?

I checked with other iPhone users in Oman, they also have an unknown number under phone, but still iMessage and Facetime are working fine.