Yes, there is a full length damper in the ABS models. I need to add some important information though, as my judgement may have been a bit unfair. I noticed when I went to the BBQ store that there is supposed to be a heat deflector in the fire box. Mine did NOT have one of these. Not sure if it was because it may have been an older model, or it was due to the fact that they didn't put it on when they delivered it. This could be a major factor in why I had the temp issues with my All-Star.
All the above being said, I did just purchase another model of the American BBQ Systems smoker. This one is called the Bar-Be-Cube. I have heard great things about this model locally so I decided to give it a try. Mainly because of the price point. I have another thread that I started about it in the forums. So far, very impressed with this model. Haven't cooked on it but I seasoned it yesterday and it held temp perfectly. I have high hopes for this one.
The Good One are definitely worth the money. I just couldn't justify the spend. For $3000 I'd rather buy a Backwoods.