A very good illustration Martyn, of how a lot of figures are made up - when they are at the castings stage. Most painters of castings are well aware, that many, if not most figures are made this way.
The manufacturer usually has one or even two or three basic body shapes - and then makes up various arms, heads, weapons - or even musical instruments to make their various "sets" - such as bands or even action figures like your two worthies here. Thus, when a purchaser buys a set - all of the decisions like poses, paint schemes etcetera, have already been made for him. He likes what he sees - and buys it - - and is very pleased with what he has. And very nice too.
The buyer of castings in kit form, however - often has a lot more choices available - including going elsewhere for the various bits and pieces he would like to use - to get the figures and poses he wants - by conversion. Once the various parts are assembled - the amount of detail and finish - is only retrained by the eyesight and ability of the painter. In the hands of an expert like "beating retreat", for example - the results are frequently stunning.
Not to say either way is right or wrong by the way - but your illustration of a minor difference to the figure by component choice shows it very neatly.
(Still wish Len's pieces were available as casrtings!!)

jb