Could you use the pellet grill without the smoker attached? Did it come with a plate to cover the exhaust that goes to the smoker?

If you click on the picture to make it larger, it appears to have a butterfly valve in that pipe between main cooking chamber and the cold smoke box.  You should be able to close it off and all of the smoke would exit through the holes at the back. There is no reason to detach the cold smoke box and put a plate over the hole.

Thanks. I did see the butterfly valve. Two reasons for my question...one is I am space limited for storing when not in use, two is it seems to be $100 cheaper than anywhere else for the grill alone. The cover and shelf are icing. Tbh I have no idea what the smoker is for...yet.

I couldn't resist. I bought one today. Not bad for my first pellet grill. 

Way to go. Enjoy that new pit! 

As I understand it , the price of that setup at Costco, is cheaper than other places sell the LG900 alone.   

I think they sell that smoker box separately for other grills, in the add on thing, it has two wheels for support on the right hand side... the setup at Costco doesn't seem to have any support at all on the right hand side, surely that's not such a brilliant way to go, no support at all for that big smoker box???     

Having said that, the price is so attractive, I'm sure a person could find a reasonable way to support it with some sort of home built legs or something.

If you look at the picture in the above link, To me it looks like the smoker box is mounted to the bottom of the grills cart. And probably is secured at the top.