Hi Monkey turned Wolf ,
I and others I know have trained hands from FMA as we are not always allowed or able to carry certain tools.
So for a FMA that trained hands and a boxer that trained hands, I would still say it depends.
Upon weight
Time in training
Dedication of the student
Their personal lives.
Now let us assume Twins in everything from what they experienced to what they ate, with the one exception of Boxing versus Hands FMA.
It could be 50/50 , yet with my bias and my experience practicing without gloves, slipping and trapping and checking would give the advantage to FMA.
That and $10 bucks I could loan you would get you a large coffee from your place of choice.

So it is my opinion. And my experience with Boxers.