You know something ...
You *could* do this ...
GK GM (base 4 attacks)
Buy him power armor to replace terminator armor. (Nothing in the rules says you can't)
He then benefits from True Grit, gaining +1 A
Or do it with a BC (base 3 attacks)
w/power armor gets True Grit gaining +1 A for 4A
Of course, you're basically losing points, but as I said you *could* do it technically.
On the bright side, this would allow your Heroes to sweeping advance with a GK squad, and they wont take up as much room in the LR/LRC, while keeping the same firepower and greater CC ability (except for saves).
Would you spend the extra 30 points (for articifer + refractor) for your BC/GM to gain +1 A and sweeping advance ability?
Speaking of articifer, I wonder if articifer armor actually counts as power armor for purposes for True Grit? What do people think? I know a lot of GK players upgrade their Justicars with articifer armor and keep True Grit ... but according to the rule for GK True Grit "...this rule only applies to Grey Knights in power armour." The entry for articifer armor does not say it is a type of power armor, only that it "offers even greater protection than power armour."
So, technically, articifer armor is NOT power armor, and so GK wearing articifer armor do not get True Grit. :huh: ?
(Personally, I think articifer is just better made power armor and so allows True Grit.)