LMT is generally thought of as good.
if i was you i would look elsewhere. GB is one of the highest priced places to buy stuff for AR-15s.
PSA and JSE seem to have the best deals and their quality is very good.
those PSA lowers along with their PSA uppers are some of the best deals out there in AR stuff.
PSA has a 14.5" m4 upper complete with bolt carrier and charging handle that is as good as any ones on sale for $399 with 1-7" twist and chrome lined bore.
there are also middys and stainless for very good prices at JSE. if you in the market you should give them a look.