L21/L29 wasnt used with the LS1 PCM, it was Black Box only to my knowledge as that's what all GMT400 trucks used. It also has the original BBC firing order where L18s have the LS style.

You may be able to find one, like 99.9% sure that combo with the OS you're looking for never appeared in the US.

I guess I'm not sure what or why you want a factory combo here? Guessing either for a swap or for COS5. I'd say just make your own "factory" tune, just use all the factory values. Most, if not all, of the tables exist in both those OS' so just copy/paste between and you should be good.