Is the stadium open for tourists at all? Wanted to stop past on a Thursday or Friday to see the stadium.

Don't think you can get inside without a ticket

Public Tours are available for $20 (or $30, if you pay for the combo tour of both Oracle Arena & the Coliseum). They're only available on days without games or events scheduled.

There are hours that the Warriors Team Store is open daily, and pre-arrranged tours of Oracle Arena leave from there. Check the Warriors and A's websites about tours and open hours for their Team Stores. The Oracle Arena tours are very highly recommended.

Not without an appointment for sure