346 brake master cylinder, W T stamp?

[1967 4K]

My 30 year old repop power disc brake master cylinder has bit the dust. I want to replace it with a GM correct 346 unit. My cars build date is first week of June 67. Should the unit have the W T stamp on the front pad or is it okay to not be there?
I have found them both ways, I was always under the impression that all used on a power disc brake cars had the W T stamp.
I’ve got a message into Mike Gibbons but today being a holiday I don’t expect a return message until later.
Thanks,