There are three prototype versions. One is an early version of the standard NTSC BIOS, one is a version of the standard NTSC BIOS and includes a built in copy of Pole Position and lastly there is the one that is an early version of the BIOS with the built in Asteroids but supports NTSC only.
There are also three newer dev BIOS releases but I don't know if you care about those.
yes, we care. do you have additional info and/or docs?