At least one variant of the 6805 has the same pinout as the 6804. The Milton chip and die don't have the part number, but one of the 6804 manuals compares the 6804 die with the 6805 die (to show that it's smaller, like you said) and the Milton die is identical to the 6805 die in that pic. I also found a book that went along with a 6805 seminar that has some parts of the 6805 die annotated. And the ROM array on the Milton die has the same weird number of bytes as the 6805 data sheet shows - 1216 (128 bytes of zero-page ROM, 964 bytes of user ROM, 116 bytes of self-test ROM and 8 bytes of vectors).

I searched for info on dumping the 6805, but it remained secret to me!