They look nice and I agree wholeheartedly about their quality and utility for games beyond just Stargrave, but are you sure you've got a Mercenaries box there? Those sure look like the Troopers box figs, which are more uniform about their armor and gear.
I mean yeah, they could be small-m mercenaries easily enough, but the box labelled Mercenaries has a more varied look to its armor with each of the five poses having slight different styles. They're really good for a paramilitary or pirate look, where the Troopers frame fits well for regular military and corporate security types.
And all the kits can swap parts easily, but you probably know that already.