It does look to be a very possible "motley" morph. However it could also easily have some Boa c. melanogaster genetic lineage as well. The scientific name literally translates to "black belly" boa. Some melanogaster can have very "blocky" rectangular saddle patterns that have sort of solid sides too, so I'm not too sure about yours.

I'm not real familiar with the precise motley origin history though other than that Dave and Tracy Barker and Ron St. Pierre first produced them many years ago. I've seen a solid black super motley the Barker's had in the past too. You will be able to find out all about your boa if you go to this link to the "Boa" forum where there are many boa morph folks that specialize and deal with countless different boa morphs and different locales on a basis.
boa forum link

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