> I can only see Ralph mentioning the 7447a as being supported
That's because in most cases the inofficial 7447B is imprecisely denoted as being 7447A. Ralph simply subsumes both A and B versions as being "A". To know for sure if it's the one or the other you'd have to see what's written on the chip. And presumably the content of the PVR register could tell it as well. But I think that the difference between A and B version isn't relevant for an OS to support both. So everything labelled "7447A" should work with MorphOS (with respect to the processor at least), no matter if it's really 7447A or rather 7447B, or even a 7447C:
