Yup.

Which means the board may or may not be original to that exact machine at all. So while it was once a 128k board, its not a 512k. But some upgraders had several on hand ready to swap in. So when someone came in, they would pull the original board and swap in an already upgraded replacement.

You can downgrade if you want. But rumor has is the original Apple-logo branded RAM chips are pretty weak. So if you downgrade you will likely end up with new chips. You will have authenticity in RAM size only.