Yes they do but apparently they are not in the store. Call them - they are about $30. You may as well specify that you want the new anti-short-stroke trigger block, but by now, that is probably all they have anyway.
Yes they sell them. Don't EVER rely on their website to be complete/accurate/up to date or rely on their email to get to them (or back to you.) KT seems to be technologically challeged at times. Give them a call. You can for sure get black and grey and OD Green (thanks TX). You might be able to get navy blue although those were a special run for a special distributor and I have not heard of anyone being able to buy one outright. They run right about $30 (+shipping) with the internal guts (hammer block and mag release) installed. Slightly less without the guts but DON'T DO IT!
Another tip - shipping is pretty much one price for anything you buy at the same time so buy your other goodies at the same time. Extra mags, +1 extensions, etc.