Strange disc. What Is It?

I saw this disk (pictured below) in the local Goodwill. I knew I wanted it but I had no idea what it was, other than it had stitch patterns depicted around the outer edges. Now if anyone has been to Goodwill, they know that when they find that cool little item, they should know to look around the general area for any other parts that may go with said "cool item". Well, after a fairly thorough search of the area, I didn't find anything that remotely looked like it went with this disk.

Problem number 1, what kind of machine did this go to? Not really a problem I guess. I still wanted it.

Problem number 2, the silly thing didn't have a price tag. I just threw caution to the wind and went to the cashier. She punched something in to her machine. She could see that I was wondering what I was being charged so she said, "Are you happy with 69 cents?" Yup

So how does one find out what something like this goes to? The internet is a wonderful tool in the right hands. I noticed on one side of the disk was the word "Gruppo". Ah-hah, my first clue. Actually my second clue. The first clue was that there were 30 stitch patterns. After a bit of searching, I found a couple very similar disks to this one, and they were for a 60s vintage Necchi sewing machine. The disk mounts in the accessories box lid, which has little cutouts for all the numbers, and shows what cam to use and what setting to put the machine to.

Ok, now we're getting somewhere. I just need to figure out what model it is goes to. That part I haven't quite figured out yet. I may just throw it on eBay and see where the bidding goes.