In his safe, Fatalwishes left a Century Arms Receiver.

It's marked as follows:

-on the magwell:

NC003XXX
Century Arms Inc
Georgia, VT
R1A1 Sporter 308 Cal
Made in USA

-inside the magwell:

METRIC

It appears to have the ejector installed.

I will eventually build it up for the Sinister, Fatalwishes' son.  Is Century good to go, or should I look for another receiver?  Are there any ambidextrous parts available, such as safeties, mag releases?  (Clearly I know very little about the FAL)

I don't know if he bought it, or if someone gave it to him.  If anyone knows how he came by it, we'd all appreciate the story, I'm sure.

That receiver will give you problems that you don't want. Century receivers with serial numbers beginning with CA (Caspian Arms) are decent receivers. The rest have a reputation for being difficult to build. 
I have access to a machine shop and enough skill to make reasonable use of it. I have built two  F A Ls with Century receivers. My "CA" Century is an excellent rifle. The other receiver was eventually cut into several pieces and put into the scrap bin so that I would not spend one more minute of my life trying to make it work.
 

Might be why he never built it, then.  Thanks.

If you're not familiar with the FAL, save yourself the potential headache and get a DSA receiver. I've built on seven of those with no issues.

DSA makes an ambidextrous selector. The magazine release is easily accessed by either hand, although lefties may have to get creative when hitting the bolt hold open release.

Well, I have my answer.  Took it to the gunshow today, tried 2 different metric mags in it.  Neither would rock in.  Will take pics & put it up in the EE or on GunBroker.

Welp - yesterday came across 3 metric mags he left, 2 still in the plastic bags.  The one open mag rocked in fine - I think @ the gun show I had no idea how to get a mag in there.  So there may be some hope yet.  Going to put it on the back burner behind the IBM M1 carbine.

People criticize the Century receivers because they use a unibrow feed ramp. Only a couple countries used a unibrow receiver while the other 90 or so used a double feed ramp. Although the double feed ramp is preferred and most common, either works just fine.  
''Either can and will work fine once set up properly''. There are many guys who have started filing on their unibrow feed ramps and ruined them. The feed ramp is not usually the place to start filing. The way rounds slide onto the feed ramp and into the chamber must be looked at as a whole. Rounds hitting the bottom of the chamber mouth is the problem most have had with a unibrow and enlarging / sloping the chamber mouth and receiver under the chamber is usually the proper fix, not sanding feed ramps. Guys ruin their receivers because they don't know what they are doing and blame the unibrow feed ramps.
Double / widow peak feed ramps tend to point the rounds up more and rounds hitting the bottom of the chamber is not as common an issue while building a FAL with a double feed ramp receiver. For a novice a double feed ramp is easier to work with because it is less likely to need adjusting from the start, more likely to just plug and play.  
Again, either type of ramp works fine once it has been set up properly. Assuming a rifle is built and working properly a unibrow ramp is actually easier to keep clean and running smooth so it has an advantage in this respect. A FAL running in full auto was likely more reliable with the unibrow ramp and likely why it was used.