Hmmm. Something so subtle could easily be a continuity error. 

Then again, with twin peaks who knows. 

The 5 + 2 = 7 seems to fit as both the name of the company as well as David Lynch's favorite number. I'm going to just guess that the 4-round fight on Bud's poster was a 2nd round knockout (I also guess it's the fight on Sarah Palmer's TV) so that's the 4 and 2.

I need to rewatch the scene again I think, but if you mean in the same shot, the five is facing him, and the two is on an adjacent side, it must be a dodgy die anyway. Opposite sides should add up to 7..... 

I just hope that this is the KEY TO EVERYTHING.

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.

Love you Murat .. always a brilliant view.