Those slots and screw holes definitely look like they're designed to hold something slightly flexible, like wood.
I tend to agree that it could be a small flag pole mount, as it also has screw hole in the base for probable attachment to a flat surface.
Yes, marine rather than aeronautical, but it's interesting that it has that long number stamp, and another "4" on the base, so it was probably mass produced.
Although the stamping raises it a bit above domestic use, (garden tool handle holder etc.) there is no military logo.
This pushes me back towards the flag pole idea. I only collect Allied aviation bits, so I'm used to seeing A*M even on components.