Very instructive pictures Brian, they also show how completely wrong I was
. Please feel free to tell me off if I go around airily speculating again!
That 4th picture is particularly fascinating, not only does it show a katar and dagger in action in what is clearly a battlefield situation, but it also seems to show stylised representations of well known types of Indian armour. The chap in the foreground seems to be wearing a mail and plate armour of the type you have just described, with the 3 rows of plates down his back. The other warrior seems to have studs on his coat and a disc on his chest, I wonder (yes, I'm speculating again) if that could be an early version of the
chihal'ta hazar masha or "coat of a thousand nails".