Hi Tammy,
First up - good luck! If you get it, you'll be laughing.
My first thought is : are you sure it's a Deluxe, and not a Safari?
If it's a Deluxe, then it's been optioned up with some very nice additions to bring it up towards Safari spec. IE, brakes, 4 jerry holders, etc. JT will be able to confirm, and if you can get the VIN then he'll be able to tell you exactly what it is.
As for the annex walls - do you *really* need them straight up? We don't have them on ours, and haven't missed them yet. We've got the kitchen-end wall, but rarely use it. If you do want to get them made later down the track, as TheNurse says, you just need to mail back the annex, which is really easy.
Hem has basically nailed the rest of it - check underneath to see if it's been abused, and check the canvas for any holes/tears/burn marks and broken zips. Check the base of the tent for damaged D-rings. Not much is terminal on these things (check the Murphy's Ck flood camper for evidence of that!), so use that to your advantage when negotiating. The distance you have to go to get it can also work in your favour if you're there on the day with cash in your hand, but are fully-well prepared to turn around and drive home again without it. The fact you've travelled that far and bought the money with will show them you're serious about doing a deal. NB - they may call your bluff on this, and you'll have to be prepared to actually turn around and leave. In that case you've learnt something about the seller anyway, and potentially it's saved you a bigger issue later.
AussieBob - our Trackabout has the VIN number welded onto the drawbar, as well as a build plate riveted on the rear showing the details about the camper (including manufacturer, etc). I'd start by taking the VIN number to JT, and seeing if he can match it. If I was looking at any brand of CT, I'd still do this step with the manufacturer - they should all keep records, and it gives you a lot more information about the trailer.
$6k - wow. That's a steal if it's in anything approaching good condition. Good luck with it - I hope it comes together for you!
Good luck!
Matto