These are A1 uppers made buy a GI contractor. Marked C and A and without blemish. Are they newly manuf. or NOS? What is the story on these?
http://www.fulton-armory.com/upperreceivera1usginofanocd.aspx

Now Out of Stock

in a previous post about these uppers per Mike at NDS...Anchor Harvey forgings made from the tooling they (AH) own. AH never bothered to remove the "C" from the tool. I Don't know who machines the forgings for Fulton Armory, but they are finished in black ceracote.

As previously stated they have a ceracote (rather than anodized) finish that some people don't like; personally I don't mind.  They do have a raised C splintered A forge code.  I have heard (but not experienced) that the charge handle trough is tight and some charge handles will not work and some say that DPMS works fine.  Mine fits well with anything. I picked this one up at a recent gun show for $100.  I am still debating what to build with it.
 

I used one on a 9mm build a few years ago. The charging handle slot was super tight, in fact I had to go through a couple of spares before I found one that even began to fit, then sand it down slightly to bare metal so that it would work.

Had no idea it was cerakoted, good to know.   While overpriced at $150, like most things AR, I have no issues with mine it has been flawless.

Cerakote. I did not know that. I have a couple forged Essential Arms lowers that are coated with something they call "Tuffcoat".

Hmmm, those uppers are a "square forge" style. Someone could cut the rebated area under/behind the port door, remove the forge codes, strip the Cerakote, and send it off to Victor for anodizing in "XM Gray". It would make a fairly good copy of an "earliest" 604 upper. All that would be missing would be the counterbore on the left side of the pivot pin hole, which there would be no reason to add.

Well that figures !!!!! I need one for an 9mm build. I hope they get more in soon.

It is my understanding that anodizing hardens the surface thereby increasing durability and corrosion resistance. I'd like to see a report(s) from someone who has run a non-anodized upper enough to know if there is a disadvantage. I believe my highest round count (several thousand is a lot for me) uppers are anodized so personally I don't know. I heard it was never a good idea to add M4 ramps to an upper "after the fact" since the bare alum was softer after the anodizing was removed. How about it?

Good receivers.  I used one on a 604 build, but switched it out for a very early square forge SP1 upper on a NDS 601 lower, as I switched to an early 602 build.  It was a perfect match for the Anderson lower it was on, for a retro-ish 604.

I've always looked at Fulton for pricing out build ideas of 'new' rifles as opposed to sourcing old parts. I'm surprised to hear, and highly skeptical, that a company like Fulton would offer a complete upper that was not anodized. Can anyone confirm that these are in fact NOT anodized? Or are these anodized and then cerakoted black to match modern rifle coloring?

These are definitely not anodized (at least the one I have isn't).
I'm using one for a 605 build (that I need to get up off my butt and finish!) and am in the process of doing what Stahlgewehr762 suggested and modifying it to look like an earlier upper. When I cut the rebate under the port door, the coating chipped away easily. Also, just by screwing the barrel nut on hand tight and removing it, the coating was worn away from the threads. Neither of which would occur as easily with a properly anodized upper.

Even though it is coated instead of anodized, the machining is still decent on the example I have. I've not run into the charging handle issue.

I'm kind of bummed they ran out of them (they've been out of those and the slick side bolt carriers for at least a couple months now, I keep checking ) I wanted to use one for my 22lr build, but, ended up going with an A2 upper instead.

The complete upper assy. built on this receiver is anodized with a ceracote finish. The purpose of anodization is corrosion resistance on the surface of the aluminum, which by itself is reactive. Anodizing doesn't necessarily produce a dark finish, but can range from a pale gold, or light grey, to much darker hues. I'd be very surprised if these forging so were ceracoted in the white.

I have used this part on  a 604 build with no issues at all, charging handle is not tight, and yes is ceracoated..

I emailed Fulton about getting these back in stock, He said it most likely will be some time in the spring.