Hi John,
does the photo show the old intake that you are saving? or the found one that your mechanic installed from his secret stash?
Either way, what makes you think the green and red marks are original?
If we have no evidence that the marks are original, and no hint of similar marks among the considerable experience with originals that is represented by our fellow forum members, I'd take them off.
The marks can always be put on -- this goes for the red and yellow dots, or the chalk digits of the Aufbaunummer, etc -- by a resourceful and knowledge restoration person. I think it shows a commendable attention to detail, even without proof that it's perfect to the original. Or maybe it's just too fine a point to argue about.