You would have to point that out, yes, and it would be nicest if you could supply references. I don't remember Cairns-Smith expressing strong views on that topic.

He tended to address the entry of carbon along the lines of:

• look, the entry of carbon came later; natural selection did it; all it needed was some possible paths, and so here is an example of one...

Ok, I reread Chapter 8 ("Entry of Carbon") in "Genetic Takeover". You are right that he mostly remains agnostic on the question of autotrophic vs heterotrophic. That, in itself is remarkable and admirable. But, in his discussion of the origin of organic chirality (pp307-308) he seems to be pretty clearly assuming heterotrophy - he talks of selecting molecules of the desired handedness from racemic mixtures, rather than simply pointing out that the chiral crystal (flaw) structure will naturally lead to chiral organic synthesis.