Mullins desk, the black die
when die on Buds desk is seen from his view, we can see 5 pips facing him and 2 pips on his right side. When we view from Dougies etc view, we see 2 on side facing them, but 4 on their left (Buds right) rather than two. Say what? Who knows what meaning, if any, Lynch may have put in with that one, but would have to be a deliberate decision & change of props
The dice are shown up front when Mullins takes over the role as working with mafia from Anthony, through his insurance company. The black is related to black life, the green(nature, law, authority, the way things are, the rule/measure, etc.) corn stalk turning black-sick-evil, then black fire we saw unleashed on Anthony when Mullins and Dougie humiliated and threatened the hero Anthony who was risking his life(and will almost definitely lose it) to 'make things right', break up the mafia corruption, etc. Mullins, the authority-boss figure here, just threatened and humiliated him, since he is not 'in' with Dougie/Mullins mafia group, the Mitchums, who now have ties with Lucky 7 Insurance(presents, cars, getting 'in' with the company, etc., they will owe the Mitchums loyalty now, exchange has started).
Hawk's map gives a lot of clues regarding colors, their symbolic meaning, and their modes of action in Twin Peaks the Return. So we have black dice, gambling, Mullins is basically taking a criminal gamble by associating his company with a mafia, since he could get busted by non-corrupt cops, maybe in the feds or somewhere(since Las Vegas PD is corrupted and incompetent, just what you would expect in 'sin city', a crime town), also they face the impending retaliation from Mr. C/Duncan's crime group.