Others will chime in, but it certainly looks like you got a single phase 220V grinder, and the 380V figure is just the switch rating. It should work (at 1680 rpm) from a regular higher-voltage outlet (e.g. oven, dryer, etc.) in your house, or with a transformer.

The plug that was (poorly) wired onto the grinder has four cords, labeled: ground, R1, S2, and T3. Any ideas what that means and how I put a regular plug on it that will fit into my transformer?

I don't know anything about 3 phase wiring, but I found this link that makes this Mazzer sound like it is wired up for 3 phase. Your plug looks the same and with the same labels. I wouldn't make conclusions based solely on the cord though, especially if it looks like a shoddy job. We need someone here who knows more about this stuff!

http://www.fam-oud.nl/~plugsocket/Belgian_3hd.html

About the switch: Switches are not specific to voltage sources or current levels, so the numbers on it mean nothing about the voltage and current levels that the switch is actually controlling. These numbers are just the maximum values the switch can handle for safe operation.

Ultimately:
My advice to you is to locate an electric motor repair shop in your area and take the grinder in to them. They will be able to tell you everything about the motor, do any necessary rewiring, and tell you how to run it. They can also change the bearings for you while they are at it. I had this done at an electric motor shop in my area for $20 (cost of parts, labor was about 10-15 minutes and given complimentary). I wouldn't think the rewiring would be too much more and you'll have the peace of mind that it is done right. If you are comfortable with working on high voltage devices, they could probably tell you what needs to be done and you could do it on your own time. If you don't understand what they tell you, don't touch it. And from your questions, I also get the feeling that you may not want to be the one monkeying around with these wires anyway. Have someone who knows what they are doing do it. It could save your life!

Im starting to think that the motor was replaced by a previous owner. There are three cords coming out of the motor rather than the usual two, and the internals look to be replaced. It also looks like whoever did it did a dodgy job of it. Ive decided to call my motor shop tomorrow and see what they make of it. Id like it to be re-wound and wired for single phase. If theyre able to drop it to 110V while theyre in there all the better.

I took my grinder to a motor shop used by my family for farm equipment. To my surprise the owner had worked on a few before. He said it couldn't be rewound because of how the motor is made, so he's going to install the necessary hardware inside the grinder case so that it works on a regular circuit, (if that turns out to be the necessity). Max cost I'm in the hole around $400-$450 for the grinder with replacement parts and servicing the motor, plus I get a fun restoration project to keep me busy for a time. Unless it turns out the motor is shot, but I doubt that since it was listed as working on 3 phase power

Usually old Mazzers just need new bearings. It's good to hear that you are still keeping a positive attitude! Sand it down with an orbital sander, paint it a color of your choice, and you'll probably be very happy with it in the end.

somewhere along the line I started seeing it as a project to get the best grinder for my use I could. Ive ordered all the replacement parts that I need to get it running, and it will hopefully be doing trials on the bar soon. I just need to figure out how to make a front plate for a semipermanent doserless mod....

espressoparts.com sells the necessary plate for less than $30: http://www.espressoparts.com/MAZ_206
A pretty good deal compared to most of the Mazzer parts. Of course you could make something out of sheet metal, but after supplies and time, you probably won't be saving a lot.

I saw the plate on espressoparts, but mine has a different arrangement of screws, so the part wouldn't really work. The doserless spout would probably fit, but I'm more worried about covering the motor. I'd just use the doser but it's filthier than the burr carrier was, and it had mold in it....