The number on the chassis hinge is the clock number of the Morgan employee who made the bonnet.
In the video about the North Cape drive, Steve Morris confirms this, also stating (if I remember correctly) that his number was 35.
However there is an exception. When John Bishop was the senior man in the body-shop, he was allowed to stamp his nickname on the hinge. i.e "Basher"
Stanley's bonnet has this stamped. I have attempted to take a photo. The hinge is at the top of the photo. Excuse the lump in the foreground, it is the body of my inspection lamp.
