I have a 1970 Cutlass Supreme Convertible. It came with a 350 2bbl. Auto Trans. The emissions decal shows "SO" in the bottom right hand corner. I'm looking for a reproduction emissions decal but I can't find the "SO" type anywhere. I can't even find reference to the "SO" type in any of the Oldsmobile manuals. The only thing I see for 1970 is 350 2bbl. AT Type "OO". Can anyone help? Why does my emissions sticker say "SO"?