[lispm]

I think this depends on which RnRS you look at.

[eatonphil]

Do some of the older ones just completely omit reserving them?

[lispm]

R6RS: pairs and lists, enclosed by ( ) or [ ] (see section 4.3.2)

[eatonphil]

Ah the problem child. :) I've mostly only paid attention to R5RS and R7RS.