As a postscript to your comment on Finicum’s dominant hand, my Dad learned to shoot rifles and shotguns left handed, until the Army convinced him to change.
We both worked on ranches and had dominant hands, but I did a lot of things left handed.
It’s an astute observation but I’m not sure it’s that material. What seems important is that he had both hands in the air until he began taking gunshot wounds.
He had a 9mms in his left pocket, but as you say he note, he might have been a rightie.
Actually, I’m the same way. I shoot a rifle right-handed, I shoot a pistol left-handed, although I can use both hands. But I can’t shoot a rifle left-handed. Not that unusual, I write with my left hand but bat and throw right handed.
All I’m saying is that if it looked like he was going for that shoulder holster they would have opened up. There are several videos on Youtube showing him armed as I have described—I suspect these officers were informed of that ahead of time if they didn’t actually watch the videos.