I did find this one in my tool box. It is in Imperial not that silly metric stuff.
It has little pins on the left side that align with the holes in face on the right, and one pin near the middle near the 7 inch mark. Somewhere I have a fold up ruler that has a brass extension on the end in a 16th of an inch.
This ruler was made in USA, and says Warranted Boxwood on the face.
Sorry for the thread hijack. I never knew that were sought after or desirable, I kept it because it was old and kinda cool.