LMT is a maker of highend AR-15's that are about as good as you can get. Carbon-15 stuff is cheap plastic crap. To say it has a Carbon-15 upper AND lower says it can't be a LMT product. My guess is that the seller meant "lower". If the price was right, I might buy a LMT upper, then throw away the Carbon-15 lower in favor of something much better.
Just my opinion, but it seems like almost a crime to put anything Carbon-15 on an LMT product.
Fear is a reaction..........Courage is a decision