The Brotherhood of Steel operating in the Mojave Wastes should be radically different from the Brotherhood on the East Coast. For one thing, they should have more advanced power armor than the T-45d model, namely the T-51b. But they should also have warriors armed in advanced combat armor because in the original games it was mainly the Paladins who were armed with Power Armor while the Knights were given combat armor and even operated more civilian roles such as manufacturing equipment.
Actually, they had their own slight variation of combat armor: http://fallout.wikia.com/wiki/Brotherhood_Armor