Brake rotor differences?

So. . . I'm in Antarctica now and since I'm almost ready to head back to the states I've started shipping myself parts to repair my '78 kz650 D Sr. I know I need a new rear brake rotor but I'm not sure which to buy on ebay. These are the two I've found

cgi.ebay.com/ebaymotors/Kawasaki-KZ650-K...sories#ht_500wt_1366

cgi.ebay.com/ebaymotors/Kawasaki-KZ-650-...sories#ht_500wt_1218

Both seem like they would fit. Any opinion on which to jump on?

Thanks

In looking through my manuals it appears that the one piece one that is not drilled looks like the ones that originally came on 1978 models. The drilled one with the rivets appears to be the 1979 and later model. It's possible that either one will work as all the info I can find on KZ650 rear disks show them as 237mm, but I cannot be sure everything else is the same. If you bike is a KZ650-D1 and you're trying to keep it stock I would take a chance on the non-drilled one.

For a second I thought the '78 D models had drilled rotors, but looking at this pic of my buddies '78 D, I don't see the holes.

His '78 had the rear caliper like a '79 C model with the rectangular sintered brake pads, and his front footpegs were two bolt mount like '79 B&C models.