The boot-lid opening has aluminium strips screwed (with chrome/brass raise-head/ovalhead screws) to it, which helps to retain the foam-rubber seal. There are 3 strips covering the left, right and top edges. The above photo shows the left and top strips. On the left strip, you can see a hole for the boot-lid lock bolt to pass through. My own 1949 AC has steel lock escutcheon plates hidden behind the aluminium strips. Curiously, the 1949 road-test AC, has the escutcheon plates over the aluninium strips.