Heheh, no bending the rules for me this year! ;)
But yeah, the 16 colours in Silicon8 don't require any new opcodes or changes to the spec or the interpreter. They are just a "creative interpretation" of the existing XO-CHIP opcode that selects the planes, and as such backwards compatible. I think it's a good rule of thumb to say that it should (be able to) run in Octo.
We've had some discussion about adding the ability to swap colours at runtime to the XO-CHIP spec, but IJ voted against it with some compelling reasons.