As far as Jubliees I know nothing, but I have a folded oyster 20mm, ref 7836 from Mary next door. She said they are from BP factory. I asked about getting another one a month or two back and she said she couldn't get them. I don't know if that's temporary or permanent. Overall it's very nice and "flimsy like the original" lol. The connecting links are figure 8 shaped but they do fit the 2mm spring bars. The clasp has one less adjust hole compared to gen.
The new Tudors from JK are shipping with folded oysters now, so maybe those can be found as parts too.
That's all I got :0