I have no idea what the missing might be be. While the frame has very basic characteristics, I'm really surprised to find hi-tensile for this era. I was expecting a seamed CrMo.

Yes, the M indicates 1996. I knew your frame was slightly newer than the OP's the moment I saw it, due to the Unicrown forks. Does it also have the small boss under the top tube, just behind the head lug?

The bicycle is not completely original. It's hard to say what might be original until we have more information and/or pictures but the Cyclone 7000 is much higher level than you would expect on a hi-tensile frame and dates to 1987-1988.