Not quite. All that the comment is talking about is that Arc lists are different from Scheme lists. In Arc, they end with the symbol 'nil (e.g., '(1 2 3) is the same as '(1 2 3 . nil)); in Scheme, they end with '() (e.g., '(1 2 3) is the same as '(1 2 3 . ())).
apply is perfectly well-defined for n arguments: (apply f x xs) is the same as (apply f (cons x xs)). In other words, if we think about apply as providing the contents of a list as arguments to a function, this is only relevant to the last argument. The rest are passed to the function normally. This is a nicety, allowing us to write things like (apply map + list-of-lists).
