Unarmoured Gallowglass?

[clibinarium]

I was wondering whether someone can clarifiy the Irish list, which makes gallowglass available as armoured or unarmoured . Can anyone tell me what the unarmoured version represents?
My understanding is that Gallowglass went into battle in helmets and mail coats, and have had trouble locating any reference to them fighting unarmoured. Anybody know the rationale behind the unarmoured types? What I've read, (and that's confined to the osprey on them, the Irish Wars osprey, the Ian Heath "Armies of the 16th Century" and Hayes McCoys 'Irish Battles') suggests that Galloglaigh were almost invariably armoured, save perhaps for a few who may have worn the "cotun" padded undercoat without the usual mail over the top, but that would that be sufficent numbers to justify classing whole units as unarmoured ?(plus the cotun gave a fair degree of protection). Even as firearms increase in abundance and they diminish in importance there dosn't seem to be any evidence that they discarded their mail as gunpowder made it obsolete. Is "unarmoured gallowglass" akin to saying "unarmoured knight"?

Trying to picture unarmoured Galloglaigh, it occured to me that perhaps the idea models men fighting in close quarters with long axes or great swords, without armour but perhaps with helmets, which might catch Redshanks with claymores or better armed Irishmen, likely to be Bonnachts as the better equiped men of a lord's army, Ian Heath suggests the axe was adopted in imitation of the Galloglaigh, much as the men depicted in the famous Derryck prints.

I am neophyte to FoG so any help would be appreciated.