2
Could not find a time... Would need a lot of research to rectify a chart for these guys, but it would be a very helpful mundane chart. A sunrise or noon chart would give you the major inflection points though.
from: https://www.jodidata.org/about-jodi/partners/opec.aspx
"OPEC was formed on September 14, 1960, at a meeting in Baghdad, the Iraqi capital, attended by five countries that became the founding members. It was registered with the United Nations Secretariat on November 6, 1962, following UN Resolution No. 6363. Also in attendance at the Baghdad meeting were - Islamic Republic of Iran, Iraq, Kuwait, Saudi Arabia and Venezuela. They signed the original agreement establishing OPEC."
Cheers,
~A.

5
The source, which I use is the research of Michael Baigent (1), who uses a report from the BBC. Baigent deduces that the schedule of the OPEC constituency must have been about 12:00 noon, since that data, I have rectified the chart I present with different events.
(1) page 354, The Book of World Horoscopes, First Published 1988.
Sincerely
Mario Raskovsky (Siderum)
www.siderum.com