Thank you so much for sharing this vital information. We will certainly search the Buren movements and the Moeris as well. Please, if in the meanwhile you discover any new information do not hesitate to let us know. Our search has been dragging on for months. This is what makes Vintage Watch Collecting so difficult. You have been very kind..
OK, you're welcome
I'd suggest trying to scour the Yahoo Japan auctions as well, Japanese vintage watch blogs, & to search for Japanese online dealer sites to see if they can be any help at least in identifying what you are looking for (in any better detail). I have links saved for some of these (Japan-based dealers & blogs), but they change over time & a few that I just tried are no longer live ... but I'm sure there are others you can find!
Finding parts for vintage Japanese watches (even those much newer than yours) of all kinds is quite a challenge. Seiko/Hattori policy seems to have been that "support" (parts availability, etc) for its models only was provided for 10 years. So many collectors of vintage '60s, '70s, and even '80s model Seikos have to be creative in finding replacement parts which are often long "out of stock" in today's official Seiko corporate facilities. Some parts have been re-created, others can be found in stocks of retired private watchmakers now being offered on venues such as eBay & Japan Yahoo auctions around the world.