I strongely suspect that was a calculated move by AMT to help sell the kit. Can't say that I blame them. Since Jefferies designed the ship, it "blended" easily with the Trek line.
Oh, yes--as in the Aurora example, companies would repackage an old kit in a heartbeat if they believed it would get a new lease on shelf life. The LE/UFO did not look like the ST ships, but it was still "alien" enough to serve as a supplement to the proper line.
...and let us not forget that cool scout ship!