On the term spangled and mottled. It appears by the APA book of Standards The white V shaped tip on a speckled susses is referred to as a spangle, it is understood that the mottling gene and several other modifying gene has contribute to this spangle. The black tip on the feather of Silver spangled hamburgs is called a spangle, but the mottling gene Did not and in no way contribute to the black spangle. I understand that there is no mottling gene in spangled hamburgs.
Now it appears that when the mottling gene is applied to a solid black bird, you will get a mottled look. Although I have seen where some breeders call their black mottled birds spangled.