I agree with all those points, Paul S.
As regards POI / POA: My MLE Mk 1 (no star) issued to a Cape colonial unit has the fixed barleycorn which is quite obviously sited over to the left. It also has the field correction, of a replacement rear sight slide also obviously off to the left. Without this rear sight, it would shoot about 2 ft to the right at 300 yds.
All my Boer Mausers (and several others I have shot) shoot exactly to the point of aim - and having a dovetail foresight any windage error would have been corrected decades ago.
As regards myths: One place where the Boer-as-marksman legend was re-born (having originated at Majuba - but that's another long story) was Spioenkop - the "acre of massacre". When you read accounts of scores of Britishin the main trench at Spioenkop all killed by shots in the right temple, it certainly sounds like uncanny Boer marksmanship. But when you walk over the ground, look at the trench, look at period photos, and see where the Boers were shooting from 400 - 1000 yds away, you'll note that (a) a huge volume of rifle fire was coming directly down the line of that straight, shallow trench from the right (b) the soldier's head was exposed (c) non-lethal wounded were taken down the hill. But it's a long climb down so the dead were not carried away. Leaving dead, head-wounded men on the summit for the numerous gruesome photographs the next morning. The legend suited the psyche of both sides -which I can sum up superficially as "Trust in God and the Mauser" and "Lions led by Donkeys".