I’ll post a WTB for this on the off chance that somebody has one lying around. This is to provide donor parts for an Ebel 6B/159. I’m not an expert on these, but it would be preferable to have one with a Breguet (over oil) hairspring as that’s correct for the 6B/159s. If not a flat hairspring one would also work. Here’s what it should look like.
https://www.ebay.com/sch/i.html?_fr...as+1187&_sacat=0&LH_TitleDesc=0&_odkw=as+1184Purchases made through these links may earn this site a commission from the eBay Partner Network
Ranfft shows AS 1158 and AS 1187 as belonging to the same family of movements. In fact, when you call up AS 1158 on his site, it is an AS 1187 that shows. Since the 1158 that is to be replaced, it appears to have a Breguet overcoil hairspring. Perhaps that might be one difference between the 1158 and the 1187. If it was my project, being an Ebel Watch, I would only be happy with an 1158.