Don't know if this is a bug but there's one guy who's guarding in the room with the sentinel and he's wearing a t-51b power armor with t-45d power helmet. Looks really strange, do any of the BoS dudes wear t-45d power armor?

I know they have T-45d Power Armor laying around the bunker and they give you a suit when you get the Power Armor Training perk, but I don't know if they ever wear it.