Yes, I suppose it could be a 1975 engine. I’m not sure when GM started using an integrated head on the 250ci, but it looks like yours isn’t an integrated head. You have a ventilation hose from the valve cover to the air cleaner which wasn’t present on a 1965 230ci, so that would suggest a 1975 engine. Pull a spark plug and feel the top of the piston with a pick.
Your picture shows the perch is behind the fuel pump, so it’s not a 292ci.
