(a) Sections 15-3-1303 through 15-3-1307, Idaho Code, do not apply to the estate of a decedent who dies prior to January 1, 2005.
(b) For the estate of a decedent who dies on or after the effective date of this act, but prior to January 1, 2005, and as to which sections 15-3-1303 through 15-3-1307, Idaho Code do not apply, estate taxes must be apportioned pursuant to the law in effect immediately before the effective date of this act.