I'm pretty adamant that it's ported based on the work of others in the scene, but this topic came up over on ASSEMblergames. I've already chimed into the discussion with what I think is true, but after re-reading that second quote above, I'm not so sure. Are we absolutely 100% sure that Sonic Jam is a port of the games? I did a cursory check, and I sure as hell didn't see any ROM headers, nor any files that would be the right size for a ROM - but if what sayin999 said is true, then you wouldn't have one, since the ROM had been separated into different chunks. If anyone wants to post in that thread and clarify some points, feel free.