I’ve been looking through pictures of these two locks, seeing many changes over time. Chubb seemed unsure what they were calling the 3G110, as it was initially the ‘New Castle’, then ‘new’ was dropped, leading to some confusion.
The 3G85 Castle was introduced in 1953 (afaik — or was it earlier?). There was also a version with detector, 3G90 5lever.
The New Castle (though seemingly just called Castle) 3G110 was the detainer lock introduced in 1960. It was soon revised because some wrong keys could jam the lock. There are 3 generations of detainer: the original one without a lip at the bottom, had to be replaced because some wrong keys could jam the lock. The second generation had a lip, and the third generation has more false notches.
There were many changes through the years. The 3G85 Castle case was originally very heavy and and formed by joining pieces with screwed blocks, later spot welding a lighter case.
Some 3G85 locks had no saw-resisting rollers in the bolt — Chubb GB690247:1951, so were they made pre-1951? Some also have the Chubb monitor lever GB445444:1936. Also, so do and some do not have false notches.
The earliest 3G110 cases had a thin strip bent around to form the case wall, spot welded to the forend. Later cases were a one-piece pressing. When the New Castle was introduced drilling was not a criminal method of attack, and anyway the drill point for an inward-opening door is behind the door stop. The lock was not initially certifiable in conformity with BS3621:1963. Later, Chubb relented and fitted drill-resisting plates so that the lock could be approved to BS3621 and so ticked insurers’ call centre boxes without quibble. On a right-hand lock, there is an alternative drill point, and for some years that was not protected.
Boxes changed over the years. As far back as I can remember, yellow boxes with clear black lettering was used. At some time, 1970s? all packaging was changed to dark blue with black lettering and pictures. Then this was later changed to a lighter blue which made everything easier to see. (Wonder how much that rebranding exercise cost?)
One of these pictures shows a very early 3G110 with a pin fitted to the cover (but the original detainers have also been replaced), and a strip attached to the back of the lockcase: do these really look like factory work? Another box, still marked ‘Patent applied for’, has a lock with silver hammer tone paint. On the face of the lock it says ‘Castle’, on the end it says ‘New Castle’.
