(a) Except as provided by Section 1103.003, an oath may be taken and subscribed or a declaration may be made, and a bond may be given and approved, at any time before:
(1) the 21st day after the date of the order granting letters of guardianship; or
(2) the letters of guardianship are revoked for a failure to qualify within the period allowed.
(b) A guardian of an estate must give a bond before being issued letters of guardianship unless a bond is not required under this title.