Here is a 5' Tall IBM 2 weight master clock. That I just bought. I'm trying to date it but the serial #. Is no were to be found.

It came out of a school.

It has a button you push that winds the 2 weights back up.

Last photo of the brass movement.

Nice clock! Here's as close as I can get:
Regulator Model 35 1940?

If you can find a serial number on it, this might help too: IBM Reference

Thanks Dave.

I'm not sure what there worth. I'm still doing research to find out.