I'm no expert but have been watching these things for the past year or so.
Assuming the following:
Its original +
Its not bent in some way that the photo doesnt show (handlebars and front fender are notorious) +
The paint, chrome and decals look as good in person as it does in the pic (Can you just clean it, polish it and go or does it need new paint?) +
The engine starts, runs, shifts and doesnt leak or smoke. +
Lights, horn works +
Brakes work +
Tires hold air - doesnt really matter you will want to replace them anyway if they are original and you actually want to ride the thing.
If all the above are true and you dont have a CT and you really want one and you can get that bike for $1000 I would buy it if I were you.
Like hornetgod says its impossible to tell from a single picture but it looks pretty nice.
If the engine is high miles then you may be looking at another 5-800 for a rebuild by someone qualified in the near future.
You can rehab the seat with new foam if its crumbly and a new cover. Check the metal seatpan to see if its cracked. (lift the seat up and look at the bottom) If its cracked you can still rehab it but its a lot more work.
Also as hornetgod says . . . if your dream is to drive it to work or the store and its not titled and plated, then you may have a huge hill to climb.
So anyway theres some stuff to consider. Buyer beware . . . its a 40 year old minibike.