Although your pictures are such poor quality it's hard to tell, most likely 'somebody' took exception to the difference between POI and POA which is common with these guns especially with commercial loads. The proper course would have been a higher front sight, and I've made one for myself in the distant past. Enfields this late in the production run often bore little identification beyond th entwined E and D logo and a I* (or I**) on the right of the body, and the barrel date, thus: '43. Serials were prefixed with a letter, which ran all through the alphabet and began again at ZA, getting at least as far as ZJ.
The usual Britishicon commercial proof marks are present, applied after it was sold off.