Mike.

This is. I repeat NOT an oem castimg master cylinder.

At least i dont remember it being one

Owner is going to pull it off this week and see if these casting numbers are in it.

If thats the case....he may try and rebuild or have it rebuilt


Edit....owner found an nos one.

Turns out the one on the car was indeed an original.
Guessing a Reman unit i came up with.

So it will go in the spares bin.
He wants to find a kit and hang on to it

Just in case