I know what the differences between the 2A and the 2A1 are. Check the action stampings they tell the story. The Indian FTR process didn't get rid of all the clues just most. The 2As came into Australiaicon first, the game was to find out who built the action the Indians or the Brits. I haven't seen a Lithgow converted. The 2A1s were not mixed as there has been no confirmation as yet.
The No4 conversion in Australia did not have a new ejector screw hole drilled, in fact most screws were removed all together if the local Central sight was used. Some other sights used that screw hole for mounting. There was no requirement to be able to eject unfired rounds, cases ejected without the screw in place.