Mk II 5* Rear Sight Base

Hi,
I am restoring a Ross Mk II 5*. I have found a Sutherland rear sight, but could use a little help finding a base.

This is what I have.
https://www.milsurps.com/images/impo.../257dabr-1.jpg

The base I am looking for will look similar to this Long Lee base, but will have an alignment pin or a hole for a alignment pin going from top to bottom in each of the four corners.
https://www.milsurps.com/images/impo...2/73ey34-1.jpg

The rear alignment pins are visible in this photo of showing rear portion of the base I am looking for.
https://www.milsurps.com/images/impo...2/f9qcjn-1.jpg

Any assistance in locating this part will be much appreciated.