In the intro ovie it has a 5th engine. dunno why but it could be a heavy lift variant of the EK-17
Those hardpoints add interest... maybe a missile platform?
So where is this 5th engine coming from then. Unless its a private transport plane?

Or a heavy lift variant that needs extra thrust?
I didn't see a 5th engine on the C-17B Globemaster III either... I'll check again.
Putting engines in the tail of an aircraft is the worst idea ever. AND they blocked off the crawlspace to the elevator actuators.
Heinkel is correct, and one of those planes, I might add, is another very successful tanker, the KC-10 Extender.
For thoughts on an AWACS variant, it is very possible, unless there is another aircraft of course that is a better candidate in AC3. Conversions from tankers to AWACS are not frequent...
Edit: Found none. The idea has some credibility, and may be useful for defensive measures in service, even if not a dedicated AWACS. The technology in that time is assumably better than today's, so an AWACS with a nose-mounted radar is possible. The Nimrod had a similar arrangement, but in the 1980s the technology to make such an arrangement feasible did not exist...
Update: I feel quite silly now... but thanks for the information, Zaku.