[Lynn Eades]

As an example of what Michael R has said, a few of the brake expanders I have seen from early carriers are dated back to 1935 1936.
Probably we were fortunate that someone pre Dunkirk could see a need and had some parts production up and running. In the case of the brake expanders, there must have been a previous application, because 1935 was too early for carriers.
In the early stages of assembly many carriers had parts fitted from the previous years production, but as you might imagine by 1942, production was streamlined to the extent that parts going on were "just made".

As you might imagine, Britian was already tooled up for production of instruments like speedos (that fitted in an existing carrier panel) Until Canada could set up specialty production lines lines, it made sense to out source those parts.
The crow bar is stopped from sliding out of the strapped socket under the right step, by the low rib on the right side of the left step. Look at pictures of other U.Cs.