As already mentioned...Chromed lined? Yes. And it says so on your link.
This is an excellent upper. All parts of it are outstanding. But it's quite overpriced in my opinion. If price is no option and this is precisely what you're looking for, buy away! If you have a careful budget, I suggest you shop around a bit.
And I say all this as a huge fan of anything BCM, with a deep stable of their products in my safe. That's just a really hefty price IMO. I see this as a $450 barreled upper with a $300 handguard. That's $750. They're asking almost $1K, delivered. There are better options IMO. Here's one (scroll down on linked page): DD 16" ML, Noveske NSR 15.5" handguard, w/ M16 BCG & CH: $789.
That's a better product IMO, for $200 less.