Yes, it’s a good deal for a gun store complete rifle.
But…
You can buy a lower receiver with internals and a stock for $250-$300 or so. The lower receiver is what’s actually considered the firearm and has to be delivered to you through a licensed firearms dealer. Gun stores will often do this for you for a $25.00 fee.
Then you can buy, through the mail, a complete upper receiver for perhaps $500-$550. Pin them together and you have a complete AR for about $800. Naturally the price will vary considerably depending on what options you want. But you can essentially design the rifle you want this way.
You won’t have a warranty. A sling ($15.00) or a magazine ($10.00) but these are very small costs compared to the roughly $200 premium you would be paying for the Armalite. Check out the Armalite website. You can get complete uppers for $500 and a complete lower (Eagle Arms) for $265.