In a bibliographical references note in an RDA record, page numbers should never be surrounded by square brackets, even when the pages mentioned do not actually have numbers printed on them. For example:
504 __ ǂa Includes bibliographical references (pages 204-208) and index.
(even if the logical page 204 doesn’t actually have that number printed on it)
More generally, the LC-PCC PS for RDA 1.7.1 regarding punctuation in notes says not to use square brackets in any notes except quoted notes. That is, only when you are quoting something that actually has brackets on it, should you include them. For example:
500 __ ǂa "The best book about punctuation, including [, ], <, and >"--Page 4 of cover.