Thanks for posting the Yahoo data, but I’m not sure that’s real either. Not all Dow stocks start trading at the same time, so as each one actually starts trading, the index drops more. That’s how the market drops 400 points in the first couple minutes of trading, as for example just happened three weeks ago. The futures were far below the “open” price, and I’m not sure any trades happened at that price either. Not three weeks ago, and not in 1987.
AFAIK, the opening price is based on the opening price of all 30 stocks, whenever they may open.
A guy saying 2247 is a buy is not saved by a delayed opening in IBM.