What's with this rear mag I bought?

I bought this set of mags (19" and 18") a while back and when I was taking the tire off the rear today, I noticed that it has two opposing bosses, each at attachment point for some sort of clamp kind of gizmo. I haven't noticed this on other Kawasaki mag wheels, which these definitely are, according to the casting marks.
They're 2.15 by 18. Beyond that, does anybody know what this wheel is? Obviously, I'm not going to be able to go tubeless.
Thanks in advance for any input.

Those two extra holes are for rim locks. They are supposed to keep the tire from spinning on the rim. They are still common on dirtbikes these days. You should be able to get a pair at any dirtbike shop. Click the link to see a rim lock: Click me for rim locks!!!

From the factory? What models came with rim locks from the factory?

they were common on rear wire wheels

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No eBay APP ID and/or Cert ID defined in Kunena configurationI'm not sure what year model it's from but I have an 18" rear mag wheel that fit my KZ1000 with the rim locks. A quick ebay search yields one ad for a 79-80 rear alloy wheel that appears to have the rim lock holes.

Fair 'nuff, then.

Now....do I need to RUN rim locks? I'm not a drag racer, nor do I play one on TV. I ride my bikes like I want them to last (because I do, because I can't afford spendy repairs).
Or do I need to paint up some of the exposed lock hardware to match the new powder coat when the time comes?
Thanks for all the answers, folks.

You would probably be ok to run without them, but I wouldn't recommend it. If the tire does slip (eg during heavy braking) it will tear the valve stem out of the tube. You don't want tires instantly going flat while you are trying to avoid an accident.

BTW, don't try to plug the holes and run tubeless, your wheels lack a crucial lip on the bead area needed to keep tires seated on the rim without a tube. You need a tube in the front as well!

If you are running a tube, then yes, you need to run rim locks. They keep the wheel from spinning inside the tire/tube and sheering off the stem.

Dang Jake, beat me to it!