Mini PCD is 4x4" which is 4x101.6mm. The manufactuing tolerance on the wheels could effectively make them, the same as 4x100, it could of course also make them that much larger than 4x101.6 . You could get them on fine with wobble bolts, but to do this you must have good center location on the hub spigot because the wobble bolts will give no centering on the studs.
Like Ollie said your bigest problem is the diameter, its unlikely that the 12" wheels will fit over your brakes. I'm sure that some early K10's came with 12" wheels, so if you really wanted them on it could be done, but you would have smaller less effective brakes.