I looked all over the State site and couldn't find SOS mentioned.
Go to their site, then click on the 'specialty maintenance' tab and you should see a new product, that I mentioned above called 'Knock Out".
I would give them a call and tell them your situation, and also ask about SOS, SOS II, and Knock Out (sounds like their latest product...call and ask about it).
It's been several years since I had to use any of this, probably close to 8 years, so it's possible they dropped the "SOS" brands and went with a newer, better product. (Meanwhile I'm researching too.)
EDIT:
Looks like they moved in 2012 from Cleveland to Mayfield Heights, Ohio. So it's quite possible things have changed on a big scale. Here's a link about their move. State Industrial Products to move headquarters, 110 jobs out of Cleveland and into Mayfield Heights | cleveland.com
Here's a bunch of products to choose from.
Graffiti Removers products - Grainger Industrial Supply