He seems to be a spotted tabby for real. But if he is "just" a spotted tabby shorthair domestic, or does have some ancestry from a purebred, we cant know.
Im rather sure he cant be purebred of pet qualtiy (where the two most probable possibilities are ocicat and bengal) - because you surely would know.
But he may had an ancestor... This we cant know. Tabby is dominant, tabby pattern will go down along the river of the life.
Spotted tabby isnt totally unusual among domestics, not common but not unique.
So it could go either way.
Anyway, he is both sweet and handsome, and so is his white comerade too...
I would say he is a very striking, Brown (black) Spotted Tabby and White, Domestic Shorthair. Is the white one his sibling? I love them both!! So cute!