It's easier to pilfer a listing these days -- here is a link so you can see the 500 fils on 10 shilling stamp.
http://iankimmerly.com/zencart/inde...cts_id=52676The overprints on the Seiyun stamps can also be found at their site.
It turns out there is an old thread on SCF on these overprints, but I missed it so I didn't reply.
https://goscf.com/t/22235Even though Scott no longer has the "For the Record" section, much of that information (actually sometimes more) can be found on the web.
Here is a decent link to a listing of Yemen. Click on the 1966 links in subsections under the section "Federation of South Arabia and States", and you will see a listing of these various overprints for the various states.
http://www.ohmygosh.on.ca/stamps/yemen/ryemen.htmSlowly rebuilding my bookmarks...
