You'll want to confirm which barrel extension type the BCL uses - almost positive is it 'DPMS' LR308 pattern - in which case you'll want matching bolt/carrier... if you decide to purchase a new one. So long as the new barrel headspaces fine when you install it, you should be good to go.
Why not start with the new barrel, and use your existing bolt/carrier - if everything works perfectly, there's no need to spend the extra money!